chore: update deps

node_modules/css-tree/lib/convertor/create.js

@@ -0,0 +1,28 @@
+import { List } from '../utils/List.js';
+
+export function createConvertor(walk) {
+    return {
+        fromPlainObject(ast) {
+            walk(ast, {
+                enter(node) {
+                    if (node.children && node.children instanceof List === false) {
+                        node.children = new List().fromArray(node.children);
+                    }
+                }
+            });
+
+            return ast;
+        },
+        toPlainObject(ast) {
+            walk(ast, {
+                leave(node) {
+                    if (node.children && node.children instanceof List) {
+                        node.children = node.children.toArray();
+                    }
+                }
+            });
+
+            return ast;
+        }
+    };
+};

node_modules/css-tree/lib/convertor/index.js

@@ -0,0 +1,4 @@
+import { createConvertor } from './create.js';
+import walker from '../walker/index.js';
+
+export default createConvertor(walker);

node_modules/css-tree/lib/data-patch.js

@@ -0,0 +1,6 @@
+import { createRequire } from 'module';
+
+const require = createRequire(import.meta.url);
+const patch = require('../data/patch.json');
+
+export default patch;

node_modules/css-tree/lib/data.js

@@ -0,0 +1,95 @@
+import { createRequire } from 'module';
+import patch from './data-patch.js';
+
+const require = createRequire(import.meta.url);
+const mdnAtrules = require('mdn-data/css/at-rules.json');
+const mdnProperties = require('mdn-data/css/properties.json');
+const mdnSyntaxes = require('mdn-data/css/syntaxes.json');
+
+const extendSyntax = /^\s*\|\s*/;
+
+function preprocessAtrules(dict) {
+    const result = Object.create(null);
+
+    for (const atruleName in dict) {
+        const atrule = dict[atruleName];
+        let descriptors = null;
+
+        if (atrule.descriptors) {
+            descriptors = Object.create(null);
+
+            for (const descriptor in atrule.descriptors) {
+                descriptors[descriptor] = atrule.descriptors[descriptor].syntax;
+            }
+        }
+
+        result[atruleName.substr(1)] = {
+            prelude: atrule.syntax.trim().replace(/\{(.|\s)+\}/, '').match(/^@\S+\s+([^;\{]*)/)[1].trim() || null,
+            descriptors
+        };
+    }
+
+    return result;
+}
+
+function patchDictionary(dict, patchDict) {
+    const result = {};
+
+    // copy all syntaxes for an original dict
+    for (const key in dict) {
+        result[key] = dict[key].syntax || dict[key];
+    }
+
+    // apply a patch
+    for (const key in patchDict) {
+        if (key in dict) {
+            if (patchDict[key].syntax) {
+                result[key] = extendSyntax.test(patchDict[key].syntax)
+                    ? result[key] + ' ' + patchDict[key].syntax.trim()
+                    : patchDict[key].syntax;
+            } else {
+                delete result[key];
+            }
+        } else {
+            if (patchDict[key].syntax) {
+                result[key] = patchDict[key].syntax.replace(extendSyntax, '');
+            }
+        }
+    }
+
+    return result;
+}
+
+function patchAtrules(dict, patchDict) {
+    const result = {};
+
+    // copy all syntaxes for an original dict
+    for (const key in dict) {
+        const patchDescriptors = (patchDict[key] && patchDict[key].descriptors) || null;
+
+        result[key] = {
+            prelude: key in patchDict && 'prelude' in patchDict[key]
+                ? patchDict[key].prelude
+                : dict[key].prelude || null,
+            descriptors: patchDictionary(dict[key].descriptors || {}, patchDescriptors || {})
+        };
+    }
+
+    // apply a patch
+    for (const key in patchDict) {
+        if (!hasOwnProperty.call(dict, key)) {
+            result[key] = {
+                prelude: patchDict[key].prelude || null,
+                descriptors: patchDict[key].descriptors && patchDictionary({}, patchDict[key].descriptors)
+            };
+        }
+    }
+
+    return result;
+}
+
+export default {
+    types: patchDictionary(mdnSyntaxes, patch.types),
+    atrules: patchAtrules(preprocessAtrules(mdnAtrules), patch.atrules),
+    properties: patchDictionary(mdnProperties, patch.properties)
+};

node_modules/css-tree/lib/definition-syntax/SyntaxError.js

@@ -0,0 +1,12 @@
+import { createCustomError } from '../utils/create-custom-error.js';
+
+export function SyntaxError(message, input, offset) {
+    return Object.assign(createCustomError('SyntaxError', message), {
+        input,
+        offset,
+        rawMessage: message,
+        message: message + '\n' +
+            '  ' + input + '\n' +
+            '--' + new Array((offset || input.length) + 1).join('-') + '^'
+    });
+};

node_modules/css-tree/lib/definition-syntax/generate.js

@@ -0,0 +1,131 @@
+function noop(value) {
+    return value;
+}
+
+function generateMultiplier(multiplier) {
+    const { min, max, comma } = multiplier;
+
+    if (min === 0 && max === 0) {
+        return comma ? '#?' : '*';
+    }
+
+    if (min === 0 && max === 1) {
+        return '?';
+    }
+
+    if (min === 1 && max === 0) {
+        return comma ? '#' : '+';
+    }
+
+    if (min === 1 && max === 1) {
+        return '';
+    }
+
+    return (
+        (comma ? '#' : '') +
+        (min === max
+            ? '{' + min + '}'
+            : '{' + min + ',' + (max !== 0 ? max : '') + '}'
+        )
+    );
+}
+
+function generateTypeOpts(node) {
+    switch (node.type) {
+        case 'Range':
+            return (
+                ' [' +
+                (node.min === null ? '-∞' : node.min) +
+                ',' +
+                (node.max === null ? '∞' : node.max) +
+                ']'
+            );
+
+        default:
+            throw new Error('Unknown node type `' + node.type + '`');
+    }
+}
+
+function generateSequence(node, decorate, forceBraces, compact) {
+    const combinator = node.combinator === ' ' || compact ? node.combinator : ' ' + node.combinator + ' ';
+    const result = node.terms
+        .map(term => internalGenerate(term, decorate, forceBraces, compact))
+        .join(combinator);
+
+    if (node.explicit || forceBraces) {
+        return (compact || result[0] === ',' ? '[' : '[ ') + result + (compact ? ']' : ' ]');
+    }
+
+    return result;
+}
+
+function internalGenerate(node, decorate, forceBraces, compact) {
+    let result;
+
+    switch (node.type) {
+        case 'Group':
+            result =
+                generateSequence(node, decorate, forceBraces, compact) +
+                (node.disallowEmpty ? '!' : '');
+            break;
+
+        case 'Multiplier':
+            // return since node is a composition
+            return (
+                internalGenerate(node.term, decorate, forceBraces, compact) +
+                decorate(generateMultiplier(node), node)
+            );
+
+        case 'Type':
+            result = '<' + node.name + (node.opts ? decorate(generateTypeOpts(node.opts), node.opts) : '') + '>';
+            break;
+
+        case 'Property':
+            result = '<\'' + node.name + '\'>';
+            break;
+
+        case 'Keyword':
+            result = node.name;
+            break;
+
+        case 'AtKeyword':
+            result = '@' + node.name;
+            break;
+
+        case 'Function':
+            result = node.name + '(';
+            break;
+
+        case 'String':
+        case 'Token':
+            result = node.value;
+            break;
+
+        case 'Comma':
+            result = ',';
+            break;
+
+        default:
+            throw new Error('Unknown node type `' + node.type + '`');
+    }
+
+    return decorate(result, node);
+}
+
+export function generate(node, options) {
+    let decorate = noop;
+    let forceBraces = false;
+    let compact = false;
+
+    if (typeof options === 'function') {
+        decorate = options;
+    } else if (options) {
+        forceBraces = Boolean(options.forceBraces);
+        compact = Boolean(options.compact);
+        if (typeof options.decorate === 'function') {
+            decorate = options.decorate;
+        }
+    }
+
+    return internalGenerate(node, decorate, forceBraces, compact);
+};

node_modules/css-tree/lib/definition-syntax/index.js

@@ -0,0 +1,4 @@
+export { SyntaxError } from './SyntaxError.js';
+export { generate } from './generate.js';
+export { parse } from './parse.js';
+export { walk } from './walk.js';

node_modules/css-tree/lib/definition-syntax/parse.js

@@ -0,0 +1,584 @@
+import { Tokenizer } from './tokenizer.js';
+
+const TAB = 9;
+const N = 10;
+const F = 12;
+const R = 13;
+const SPACE = 32;
+const EXCLAMATIONMARK = 33;    // !
+const NUMBERSIGN = 35;         // #
+const AMPERSAND = 38;          // &
+const APOSTROPHE = 39;         // '
+const LEFTPARENTHESIS = 40;    // (
+const RIGHTPARENTHESIS = 41;   // )
+const ASTERISK = 42;           // *
+const PLUSSIGN = 43;           // +
+const COMMA = 44;              // ,
+const HYPERMINUS = 45;         // -
+const LESSTHANSIGN = 60;       // <
+const GREATERTHANSIGN = 62;    // >
+const QUESTIONMARK = 63;       // ?
+const COMMERCIALAT = 64;       // @
+const LEFTSQUAREBRACKET = 91;  // [
+const RIGHTSQUAREBRACKET = 93; // ]
+const LEFTCURLYBRACKET = 123;  // {
+const VERTICALLINE = 124;      // |
+const RIGHTCURLYBRACKET = 125; // }
+const INFINITY = 8734;         // ∞
+const NAME_CHAR = new Uint8Array(128).map((_, idx) =>
+    /[a-zA-Z0-9\-]/.test(String.fromCharCode(idx)) ? 1 : 0
+);
+const COMBINATOR_PRECEDENCE = {
+    ' ': 1,
+    '&&': 2,
+    '||': 3,
+    '|': 4
+};
+
+function scanSpaces(tokenizer) {
+    return tokenizer.substringToPos(
+        tokenizer.findWsEnd(tokenizer.pos)
+    );
+}
+
+function scanWord(tokenizer) {
+    let end = tokenizer.pos;
+
+    for (; end < tokenizer.str.length; end++) {
+        const code = tokenizer.str.charCodeAt(end);
+        if (code >= 128 || NAME_CHAR[code] === 0) {
+            break;
+        }
+    }
+
+    if (tokenizer.pos === end) {
+        tokenizer.error('Expect a keyword');
+    }
+
+    return tokenizer.substringToPos(end);
+}
+
+function scanNumber(tokenizer) {
+    let end = tokenizer.pos;
+
+    for (; end < tokenizer.str.length; end++) {
+        const code = tokenizer.str.charCodeAt(end);
+        if (code < 48 || code > 57) {
+            break;
+        }
+    }
+
+    if (tokenizer.pos === end) {
+        tokenizer.error('Expect a number');
+    }
+
+    return tokenizer.substringToPos(end);
+}
+
+function scanString(tokenizer) {
+    const end = tokenizer.str.indexOf('\'', tokenizer.pos + 1);
+
+    if (end === -1) {
+        tokenizer.pos = tokenizer.str.length;
+        tokenizer.error('Expect an apostrophe');
+    }
+
+    return tokenizer.substringToPos(end + 1);
+}
+
+function readMultiplierRange(tokenizer) {
+    let min = null;
+    let max = null;
+
+    tokenizer.eat(LEFTCURLYBRACKET);
+
+    min = scanNumber(tokenizer);
+
+    if (tokenizer.charCode() === COMMA) {
+        tokenizer.pos++;
+        if (tokenizer.charCode() !== RIGHTCURLYBRACKET) {
+            max = scanNumber(tokenizer);
+        }
+    } else {
+        max = min;
+    }
+
+    tokenizer.eat(RIGHTCURLYBRACKET);
+
+    return {
+        min: Number(min),
+        max: max ? Number(max) : 0
+    };
+}
+
+function readMultiplier(tokenizer) {
+    let range = null;
+    let comma = false;
+
+    switch (tokenizer.charCode()) {
+        case ASTERISK:
+            tokenizer.pos++;
+
+            range = {
+                min: 0,
+                max: 0
+            };
+
+            break;
+
+        case PLUSSIGN:
+            tokenizer.pos++;
+
+            range = {
+                min: 1,
+                max: 0
+            };
+
+            break;
+
+        case QUESTIONMARK:
+            tokenizer.pos++;
+
+            range = {
+                min: 0,
+                max: 1
+            };
+
+            break;
+
+        case NUMBERSIGN:
+            tokenizer.pos++;
+
+            comma = true;
+
+            if (tokenizer.charCode() === LEFTCURLYBRACKET) {
+                range = readMultiplierRange(tokenizer);
+            } else if (tokenizer.charCode() === QUESTIONMARK) {
+                // https://www.w3.org/TR/css-values-4/#component-multipliers
+                // > the # and ? multipliers may be stacked as #?
+                // In this case just treat "#?" as a single multiplier
+                // { min: 0, max: 0, comma: true }
+                tokenizer.pos++;
+                range = {
+                    min: 0,
+                    max: 0
+                };
+            } else {
+                range = {
+                    min: 1,
+                    max: 0
+                };
+            }
+
+            break;
+
+        case LEFTCURLYBRACKET:
+            range = readMultiplierRange(tokenizer);
+            break;
+
+        default:
+            return null;
+    }
+
+    return {
+        type: 'Multiplier',
+        comma,
+        min: range.min,
+        max: range.max,
+        term: null
+    };
+}
+
+function maybeMultiplied(tokenizer, node) {
+    const multiplier = readMultiplier(tokenizer);
+
+    if (multiplier !== null) {
+        multiplier.term = node;
+
+        // https://www.w3.org/TR/css-values-4/#component-multipliers
+        // > The + and # multipliers may be stacked as +#;
+        // Represent "+#" as nested multipliers:
+        // { ...<multiplier #>,
+        //   term: {
+        //     ...<multipler +>,
+        //     term: node
+        //   }
+        // }
+        if (tokenizer.charCode() === NUMBERSIGN &&
+            tokenizer.charCodeAt(tokenizer.pos - 1) === PLUSSIGN) {
+            return maybeMultiplied(tokenizer, multiplier);
+        }
+
+        return multiplier;
+    }
+
+    return node;
+}
+
+function maybeToken(tokenizer) {
+    const ch = tokenizer.peek();
+
+    if (ch === '') {
+        return null;
+    }
+
+    return {
+        type: 'Token',
+        value: ch
+    };
+}
+
+function readProperty(tokenizer) {
+    let name;
+
+    tokenizer.eat(LESSTHANSIGN);
+    tokenizer.eat(APOSTROPHE);
+
+    name = scanWord(tokenizer);
+
+    tokenizer.eat(APOSTROPHE);
+    tokenizer.eat(GREATERTHANSIGN);
+
+    return maybeMultiplied(tokenizer, {
+        type: 'Property',
+        name
+    });
+}
+
+// https://drafts.csswg.org/css-values-3/#numeric-ranges
+// 4.1. Range Restrictions and Range Definition Notation
+//
+// Range restrictions can be annotated in the numeric type notation using CSS bracketed
+// range notation—[min,max]—within the angle brackets, after the identifying keyword,
+// indicating a closed range between (and including) min and max.
+// For example, <integer [0, 10]> indicates an integer between 0 and 10, inclusive.
+function readTypeRange(tokenizer) {
+    // use null for Infinity to make AST format JSON serializable/deserializable
+    let min = null; // -Infinity
+    let max = null; // Infinity
+    let sign = 1;
+
+    tokenizer.eat(LEFTSQUAREBRACKET);
+
+    if (tokenizer.charCode() === HYPERMINUS) {
+        tokenizer.peek();
+        sign = -1;
+    }
+
+    if (sign == -1 && tokenizer.charCode() === INFINITY) {
+        tokenizer.peek();
+    } else {
+        min = sign * Number(scanNumber(tokenizer));
+
+        if (NAME_CHAR[tokenizer.charCode()] !== 0) {
+            min += scanWord(tokenizer);
+        }
+    }
+
+    scanSpaces(tokenizer);
+    tokenizer.eat(COMMA);
+    scanSpaces(tokenizer);
+
+    if (tokenizer.charCode() === INFINITY) {
+        tokenizer.peek();
+    } else {
+        sign = 1;
+
+        if (tokenizer.charCode() === HYPERMINUS) {
+            tokenizer.peek();
+            sign = -1;
+        }
+
+        max = sign * Number(scanNumber(tokenizer));
+
+        if (NAME_CHAR[tokenizer.charCode()] !== 0) {
+            max += scanWord(tokenizer);
+        }
+    }
+
+    tokenizer.eat(RIGHTSQUAREBRACKET);
+
+    return {
+        type: 'Range',
+        min,
+        max
+    };
+}
+
+function readType(tokenizer) {
+    let name;
+    let opts = null;
+
+    tokenizer.eat(LESSTHANSIGN);
+    name = scanWord(tokenizer);
+
+    if (tokenizer.charCode() === LEFTPARENTHESIS &&
+        tokenizer.nextCharCode() === RIGHTPARENTHESIS) {
+        tokenizer.pos += 2;
+        name += '()';
+    }
+
+    if (tokenizer.charCodeAt(tokenizer.findWsEnd(tokenizer.pos)) === LEFTSQUAREBRACKET) {
+        scanSpaces(tokenizer);
+        opts = readTypeRange(tokenizer);
+    }
+
+    tokenizer.eat(GREATERTHANSIGN);
+
+    return maybeMultiplied(tokenizer, {
+        type: 'Type',
+        name,
+        opts
+    });
+}
+
+function readKeywordOrFunction(tokenizer) {
+    const name = scanWord(tokenizer);
+
+    if (tokenizer.charCode() === LEFTPARENTHESIS) {
+        tokenizer.pos++;
+
+        return {
+            type: 'Function',
+            name
+        };
+    }
+
+    return maybeMultiplied(tokenizer, {
+        type: 'Keyword',
+        name
+    });
+}
+
+function regroupTerms(terms, combinators) {
+    function createGroup(terms, combinator) {
+        return {
+            type: 'Group',
+            terms,
+            combinator,
+            disallowEmpty: false,
+            explicit: false
+        };
+    }
+
+    let combinator;
+
+    combinators = Object.keys(combinators)
+        .sort((a, b) => COMBINATOR_PRECEDENCE[a] - COMBINATOR_PRECEDENCE[b]);
+
+    while (combinators.length > 0) {
+        combinator = combinators.shift();
+
+        let i = 0;
+        let subgroupStart = 0;
+
+        for (; i < terms.length; i++) {
+            const term = terms[i];
+
+            if (term.type === 'Combinator') {
+                if (term.value === combinator) {
+                    if (subgroupStart === -1) {
+                        subgroupStart = i - 1;
+                    }
+                    terms.splice(i, 1);
+                    i--;
+                } else {
+                    if (subgroupStart !== -1 && i - subgroupStart > 1) {
+                        terms.splice(
+                            subgroupStart,
+                            i - subgroupStart,
+                            createGroup(terms.slice(subgroupStart, i), combinator)
+                        );
+                        i = subgroupStart + 1;
+                    }
+                    subgroupStart = -1;
+                }
+            }
+        }
+
+        if (subgroupStart !== -1 && combinators.length) {
+            terms.splice(
+                subgroupStart,
+                i - subgroupStart,
+                createGroup(terms.slice(subgroupStart, i), combinator)
+            );
+        }
+    }
+
+    return combinator;
+}
+
+function readImplicitGroup(tokenizer) {
+    const terms = [];
+    const combinators = {};
+    let token;
+    let prevToken = null;
+    let prevTokenPos = tokenizer.pos;
+
+    while (token = peek(tokenizer)) {
+        if (token.type !== 'Spaces') {
+            if (token.type === 'Combinator') {
+                // check for combinator in group beginning and double combinator sequence
+                if (prevToken === null || prevToken.type === 'Combinator') {
+                    tokenizer.pos = prevTokenPos;
+                    tokenizer.error('Unexpected combinator');
+                }
+
+                combinators[token.value] = true;
+            } else if (prevToken !== null && prevToken.type !== 'Combinator') {
+                combinators[' '] = true;  // a b
+                terms.push({
+                    type: 'Combinator',
+                    value: ' '
+                });
+            }
+
+            terms.push(token);
+            prevToken = token;
+            prevTokenPos = tokenizer.pos;
+        }
+    }
+
+    // check for combinator in group ending
+    if (prevToken !== null && prevToken.type === 'Combinator') {
+        tokenizer.pos -= prevTokenPos;
+        tokenizer.error('Unexpected combinator');
+    }
+
+    return {
+        type: 'Group',
+        terms,
+        combinator: regroupTerms(terms, combinators) || ' ',
+        disallowEmpty: false,
+        explicit: false
+    };
+}
+
+function readGroup(tokenizer) {
+    let result;
+
+    tokenizer.eat(LEFTSQUAREBRACKET);
+    result = readImplicitGroup(tokenizer);
+    tokenizer.eat(RIGHTSQUAREBRACKET);
+
+    result.explicit = true;
+
+    if (tokenizer.charCode() === EXCLAMATIONMARK) {
+        tokenizer.pos++;
+        result.disallowEmpty = true;
+    }
+
+    return result;
+}
+
+function peek(tokenizer) {
+    let code = tokenizer.charCode();
+
+    if (code < 128 && NAME_CHAR[code] === 1) {
+        return readKeywordOrFunction(tokenizer);
+    }
+
+    switch (code) {
+        case RIGHTSQUAREBRACKET:
+            // don't eat, stop scan a group
+            break;
+
+        case LEFTSQUAREBRACKET:
+            return maybeMultiplied(tokenizer, readGroup(tokenizer));
+
+        case LESSTHANSIGN:
+            return tokenizer.nextCharCode() === APOSTROPHE
+                ? readProperty(tokenizer)
+                : readType(tokenizer);
+
+        case VERTICALLINE:
+            return {
+                type: 'Combinator',
+                value: tokenizer.substringToPos(
+                    tokenizer.pos + (tokenizer.nextCharCode() === VERTICALLINE ? 2 : 1)
+                )
+            };
+
+        case AMPERSAND:
+            tokenizer.pos++;
+            tokenizer.eat(AMPERSAND);
+
+            return {
+                type: 'Combinator',
+                value: '&&'
+            };
+
+        case COMMA:
+            tokenizer.pos++;
+            return {
+                type: 'Comma'
+            };
+
+        case APOSTROPHE:
+            return maybeMultiplied(tokenizer, {
+                type: 'String',
+                value: scanString(tokenizer)
+            });
+
+        case SPACE:
+        case TAB:
+        case N:
+        case R:
+        case F:
+            return {
+                type: 'Spaces',
+                value: scanSpaces(tokenizer)
+            };
+
+        case COMMERCIALAT:
+            code = tokenizer.nextCharCode();
+
+            if (code < 128 && NAME_CHAR[code] === 1) {
+                tokenizer.pos++;
+                return {
+                    type: 'AtKeyword',
+                    name: scanWord(tokenizer)
+                };
+            }
+
+            return maybeToken(tokenizer);
+
+        case ASTERISK:
+        case PLUSSIGN:
+        case QUESTIONMARK:
+        case NUMBERSIGN:
+        case EXCLAMATIONMARK:
+            // prohibited tokens (used as a multiplier start)
+            break;
+
+        case LEFTCURLYBRACKET:
+            // LEFTCURLYBRACKET is allowed since mdn/data uses it w/o quoting
+            // check next char isn't a number, because it's likely a disjoined multiplier
+            code = tokenizer.nextCharCode();
+
+            if (code < 48 || code > 57) {
+                return maybeToken(tokenizer);
+            }
+
+            break;
+
+        default:
+            return maybeToken(tokenizer);
+    }
+}
+
+export function parse(source) {
+    const tokenizer = new Tokenizer(source);
+    const result = readImplicitGroup(tokenizer);
+
+    if (tokenizer.pos !== source.length) {
+        tokenizer.error('Unexpected input');
+    }
+
+    // reduce redundant groups with single group term
+    if (result.terms.length === 1 && result.terms[0].type === 'Group') {
+        return result.terms[0];
+    }
+
+    return result;
+};

node_modules/css-tree/lib/definition-syntax/tokenizer.js

@@ -0,0 +1,52 @@
+import { SyntaxError } from './SyntaxError.js';
+
+const TAB = 9;
+const N = 10;
+const F = 12;
+const R = 13;
+const SPACE = 32;
+
+export class Tokenizer {
+    constructor(str) {
+        this.str = str;
+        this.pos = 0;
+    }
+    charCodeAt(pos) {
+        return pos < this.str.length ? this.str.charCodeAt(pos) : 0;
+    }
+    charCode() {
+        return this.charCodeAt(this.pos);
+    }
+    nextCharCode() {
+        return this.charCodeAt(this.pos + 1);
+    }
+    nextNonWsCode(pos) {
+        return this.charCodeAt(this.findWsEnd(pos));
+    }
+    findWsEnd(pos) {
+        for (; pos < this.str.length; pos++) {
+            const code = this.str.charCodeAt(pos);
+            if (code !== R && code !== N && code !== F && code !== SPACE && code !== TAB) {
+                break;
+            }
+        }
+
+        return pos;
+    }
+    substringToPos(end) {
+        return this.str.substring(this.pos, this.pos = end);
+    }
+    eat(code) {
+        if (this.charCode() !== code) {
+            this.error('Expect `' + String.fromCharCode(code) + '`');
+        }
+
+        this.pos++;
+    }
+    peek() {
+        return this.pos < this.str.length ? this.str.charAt(this.pos++) : '';
+    }
+    error(message) {
+        throw new SyntaxError(message, this.str, this.pos);
+    }
+};

node_modules/css-tree/lib/definition-syntax/walk.js

@@ -0,0 +1,52 @@
+const noop = function() {};
+
+function ensureFunction(value) {
+    return typeof value === 'function' ? value : noop;
+}
+
+export function walk(node, options, context) {
+    function walk(node) {
+        enter.call(context, node);
+
+        switch (node.type) {
+            case 'Group':
+                node.terms.forEach(walk);
+                break;
+
+            case 'Multiplier':
+                walk(node.term);
+                break;
+
+            case 'Type':
+            case 'Property':
+            case 'Keyword':
+            case 'AtKeyword':
+            case 'Function':
+            case 'String':
+            case 'Token':
+            case 'Comma':
+                break;
+
+            default:
+                throw new Error('Unknown type: ' + node.type);
+        }
+
+        leave.call(context, node);
+    }
+
+    let enter = noop;
+    let leave = noop;
+
+    if (typeof options === 'function') {
+        enter = options;
+    } else if (options) {
+        enter = ensureFunction(options.enter);
+        leave = ensureFunction(options.leave);
+    }
+
+    if (enter === noop && leave === noop) {
+        throw new Error('Neither `enter` nor `leave` walker handler is set or both aren\'t a function');
+    }
+
+    walk(node, context);
+};

node_modules/css-tree/lib/generator/create.js

@@ -0,0 +1,98 @@
+import { tokenize, Delim, WhiteSpace } from '../tokenizer/index.js';
+import { generateSourceMap } from './sourceMap.js';
+import * as tokenBefore from './token-before.js';
+
+const REVERSESOLIDUS = 0x005c; // U+005C REVERSE SOLIDUS (\)
+
+function processChildren(node, delimeter) {
+    if (typeof delimeter === 'function') {
+        let prev = null;
+
+        node.children.forEach(node => {
+            if (prev !== null) {
+                delimeter.call(this, prev);
+            }
+
+            this.node(node);
+            prev = node;
+        });
+
+        return;
+    }
+
+    node.children.forEach(this.node, this);
+}
+
+function processChunk(chunk) {
+    tokenize(chunk, (type, start, end) => {
+        this.token(type, chunk.slice(start, end));
+    });
+}
+
+export function createGenerator(config) {
+    const types = new Map();
+
+    for (let name in config.node) {
+        const item = config.node[name];
+        const fn = item.generate || item;
+
+        if (typeof fn === 'function') {
+            types.set(name, item.generate || item);
+        }
+    }
+
+    return function(node, options) {
+        let buffer = '';
+        let prevCode = 0;
+        let handlers = {
+            node(node) {
+                if (types.has(node.type)) {
+                    types.get(node.type).call(publicApi, node);
+                } else {
+                    throw new Error('Unknown node type: ' + node.type);
+                }
+            },
+            tokenBefore: tokenBefore.safe,
+            token(type, value) {
+                prevCode = this.tokenBefore(prevCode, type, value);
+
+                this.emit(value, type, false);
+
+                if (type === Delim && value.charCodeAt(0) === REVERSESOLIDUS) {
+                    this.emit('\n', WhiteSpace, true);
+                }
+            },
+            emit(value) {
+                buffer += value;
+            },
+            result() {
+                return buffer;
+            }
+        };
+
+        if (options) {
+            if (typeof options.decorator === 'function') {
+                handlers = options.decorator(handlers);
+            }
+
+            if (options.sourceMap) {
+                handlers = generateSourceMap(handlers);
+            }
+
+            if (options.mode in tokenBefore) {
+                handlers.tokenBefore = tokenBefore[options.mode];
+            }
+        }
+
+        const publicApi = {
+            node: (node) => handlers.node(node),
+            children: processChildren,
+            token: (type, value) => handlers.token(type, value),
+            tokenize: processChunk
+        };
+
+        handlers.node(node);
+
+        return handlers.result();
+    };
+};

node_modules/css-tree/lib/generator/index.js

@@ -0,0 +1,4 @@
+import { createGenerator } from './create.js';
+import config from '../syntax/config/generator.js';
+
+export default createGenerator(config);

node_modules/css-tree/lib/generator/sourceMap.js

@@ -0,0 +1,92 @@
+import { SourceMapGenerator } from 'source-map-js/lib/source-map-generator.js';
+
+const trackNodes = new Set(['Atrule', 'Selector', 'Declaration']);
+
+export function generateSourceMap(handlers) {
+    const map = new SourceMapGenerator();
+    const generated = {
+        line: 1,
+        column: 0
+    };
+    const original = {
+        line: 0, // should be zero to add first mapping
+        column: 0
+    };
+    const activatedGenerated = {
+        line: 1,
+        column: 0
+    };
+    const activatedMapping = {
+        generated: activatedGenerated
+    };
+    let line = 1;
+    let column = 0;
+    let sourceMappingActive = false;
+
+    const origHandlersNode = handlers.node;
+    handlers.node = function(node) {
+        if (node.loc && node.loc.start && trackNodes.has(node.type)) {
+            const nodeLine = node.loc.start.line;
+            const nodeColumn = node.loc.start.column - 1;
+
+            if (original.line !== nodeLine ||
+                original.column !== nodeColumn) {
+                original.line = nodeLine;
+                original.column = nodeColumn;
+
+                generated.line = line;
+                generated.column = column;
+
+                if (sourceMappingActive) {
+                    sourceMappingActive = false;
+                    if (generated.line !== activatedGenerated.line ||
+                        generated.column !== activatedGenerated.column) {
+                        map.addMapping(activatedMapping);
+                    }
+                }
+
+                sourceMappingActive = true;
+                map.addMapping({
+                    source: node.loc.source,
+                    original,
+                    generated
+                });
+            }
+        }
+
+        origHandlersNode.call(this, node);
+
+        if (sourceMappingActive && trackNodes.has(node.type)) {
+            activatedGenerated.line = line;
+            activatedGenerated.column = column;
+        }
+    };
+
+    const origHandlersEmit = handlers.emit;
+    handlers.emit = function(value, type, auto) {
+        for (let i = 0; i < value.length; i++) {
+            if (value.charCodeAt(i) === 10) { // \n
+                line++;
+                column = 0;
+            } else {
+                column++;
+            }
+        }
+
+        origHandlersEmit(value, type, auto);
+    };
+
+    const origHandlersResult = handlers.result;
+    handlers.result = function() {
+        if (sourceMappingActive) {
+            map.addMapping(activatedMapping);
+        }
+
+        return {
+            css: origHandlersResult(),
+            map
+        };
+    };
+
+    return handlers;
+};

node_modules/css-tree/lib/generator/token-before.js

@@ -0,0 +1,182 @@
+import {
+    WhiteSpace,
+    Delim,
+    Ident,
+    Function as FunctionToken,
+    Url,
+    BadUrl,
+    AtKeyword,
+    Hash,
+    Percentage,
+    Dimension,
+    Number as NumberToken,
+    String as StringToken,
+    Colon,
+    LeftParenthesis,
+    RightParenthesis,
+    CDC
+} from '../tokenizer/index.js';
+
+const PLUSSIGN = 0x002B;    // U+002B PLUS SIGN (+)
+const HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
+
+const code = (type, value) => {
+    if (type === Delim) {
+        type = value;
+    }
+
+    if (typeof type === 'string') {
+        const charCode = type.charCodeAt(0);
+        return charCode > 0x7F ? 0x8000 : charCode << 8;
+    }
+
+    return type;
+};
+
+// https://www.w3.org/TR/css-syntax-3/#serialization
+// The only requirement for serialization is that it must "round-trip" with parsing,
+// that is, parsing the stylesheet must produce the same data structures as parsing,
+// serializing, and parsing again, except for consecutive <whitespace-token>s,
+// which may be collapsed into a single token.
+
+const specPairs = [
+    [Ident, Ident],
+    [Ident, FunctionToken],
+    [Ident, Url],
+    [Ident, BadUrl],
+    [Ident, '-'],
+    [Ident, NumberToken],
+    [Ident, Percentage],
+    [Ident, Dimension],
+    [Ident, CDC],
+    [Ident, LeftParenthesis],
+
+    [AtKeyword, Ident],
+    [AtKeyword, FunctionToken],
+    [AtKeyword, Url],
+    [AtKeyword, BadUrl],
+    [AtKeyword, '-'],
+    [AtKeyword, NumberToken],
+    [AtKeyword, Percentage],
+    [AtKeyword, Dimension],
+    [AtKeyword, CDC],
+
+    [Hash, Ident],
+    [Hash, FunctionToken],
+    [Hash, Url],
+    [Hash, BadUrl],
+    [Hash, '-'],
+    [Hash, NumberToken],
+    [Hash, Percentage],
+    [Hash, Dimension],
+    [Hash, CDC],
+
+    [Dimension, Ident],
+    [Dimension, FunctionToken],
+    [Dimension, Url],
+    [Dimension, BadUrl],
+    [Dimension, '-'],
+    [Dimension, NumberToken],
+    [Dimension, Percentage],
+    [Dimension, Dimension],
+    [Dimension, CDC],
+
+    ['#', Ident],
+    ['#', FunctionToken],
+    ['#', Url],
+    ['#', BadUrl],
+    ['#', '-'],
+    ['#', NumberToken],
+    ['#', Percentage],
+    ['#', Dimension],
+    ['#', CDC], // https://github.com/w3c/csswg-drafts/pull/6874
+
+    ['-', Ident],
+    ['-', FunctionToken],
+    ['-', Url],
+    ['-', BadUrl],
+    ['-', '-'],
+    ['-', NumberToken],
+    ['-', Percentage],
+    ['-', Dimension],
+    ['-', CDC], // https://github.com/w3c/csswg-drafts/pull/6874
+
+    [NumberToken, Ident],
+    [NumberToken, FunctionToken],
+    [NumberToken, Url],
+    [NumberToken, BadUrl],
+    [NumberToken, NumberToken],
+    [NumberToken, Percentage],
+    [NumberToken, Dimension],
+    [NumberToken, '%'],
+    [NumberToken, CDC], // https://github.com/w3c/csswg-drafts/pull/6874
+
+    ['@', Ident],
+    ['@', FunctionToken],
+    ['@', Url],
+    ['@', BadUrl],
+    ['@', '-'],
+    ['@', CDC], // https://github.com/w3c/csswg-drafts/pull/6874
+
+    ['.', NumberToken],
+    ['.', Percentage],
+    ['.', Dimension],
+
+    ['+', NumberToken],
+    ['+', Percentage],
+    ['+', Dimension],
+
+    ['/', '*']
+];
+// validate with scripts/generate-safe
+const safePairs = specPairs.concat([
+    [Ident, Hash],
+
+    [Dimension, Hash],
+
+    [Hash, Hash],
+
+    [AtKeyword, LeftParenthesis],
+    [AtKeyword, StringToken],
+    [AtKeyword, Colon],
+
+    [Percentage, Percentage],
+    [Percentage, Dimension],
+    [Percentage, FunctionToken],
+    [Percentage, '-'],
+
+    [RightParenthesis, Ident],
+    [RightParenthesis, FunctionToken],
+    [RightParenthesis, Percentage],
+    [RightParenthesis, Dimension],
+    [RightParenthesis, Hash],
+    [RightParenthesis, '-']
+]);
+
+function createMap(pairs) {
+    const isWhiteSpaceRequired = new Set(
+        pairs.map(([prev, next]) => (code(prev) << 16 | code(next)))
+    );
+
+    return function(prevCode, type, value) {
+        const nextCode = code(type, value);
+        const nextCharCode = value.charCodeAt(0);
+        const emitWs =
+            (nextCharCode === HYPHENMINUS &&
+                type !== Ident &&
+                type !== FunctionToken &&
+                type !== CDC) ||
+            (nextCharCode === PLUSSIGN)
+                ? isWhiteSpaceRequired.has(prevCode << 16 | nextCharCode << 8)
+                : isWhiteSpaceRequired.has(prevCode << 16 | nextCode);
+
+        if (emitWs) {
+            this.emit(' ', WhiteSpace, true);
+        }
+
+        return nextCode;
+    };
+}
+
+export const spec = createMap(specPairs);
+export const safe = createMap(safePairs);

node_modules/css-tree/lib/index.js

@@ -0,0 +1,30 @@
+import syntax from './syntax/index.js';
+
+export * from './version.js';
+export { default as createSyntax } from './syntax/create.js';
+export { List } from './utils/List.js';
+export { Lexer } from './lexer/Lexer.js';
+export { tokenTypes, tokenNames, TokenStream } from './tokenizer/index.js';
+export * as definitionSyntax from './definition-syntax/index.js';
+export { clone } from './utils/clone.js';
+export * from './utils/names.js';
+export * as ident from './utils/ident.js';
+export * as string from './utils/string.js';
+export * as url from './utils/url.js';
+export const {
+    tokenize,
+    parse,
+    generate,
+    lexer,
+    createLexer,
+
+    walk,
+    find,
+    findLast,
+    findAll,
+
+    toPlainObject,
+    fromPlainObject,
+
+    fork
+} = syntax;

node_modules/css-tree/lib/lexer/Lexer.js

@@ -0,0 +1,453 @@
+import { SyntaxReferenceError, SyntaxMatchError } from './error.js';
+import * as names from '../utils/names.js';
+import { cssWideKeywords } from './generic-const.js';
+import generic from './generic.js';
+import { parse, generate, walk } from '../definition-syntax/index.js';
+import prepareTokens from './prepare-tokens.js';
+import { buildMatchGraph } from './match-graph.js';
+import { matchAsTree } from './match.js';
+import * as trace from './trace.js';
+import { matchFragments } from './search.js';
+import { getStructureFromConfig } from './structure.js';
+
+const cssWideKeywordsSyntax = buildMatchGraph(cssWideKeywords.join(' | '));
+
+function dumpMapSyntax(map, compact, syntaxAsAst) {
+    const result = {};
+
+    for (const name in map) {
+        if (map[name].syntax) {
+            result[name] = syntaxAsAst
+                ? map[name].syntax
+                : generate(map[name].syntax, { compact });
+        }
+    }
+
+    return result;
+}
+
+function dumpAtruleMapSyntax(map, compact, syntaxAsAst) {
+    const result = {};
+
+    for (const [name, atrule] of Object.entries(map)) {
+        result[name] = {
+            prelude: atrule.prelude && (
+                syntaxAsAst
+                    ? atrule.prelude.syntax
+                    : generate(atrule.prelude.syntax, { compact })
+            ),
+            descriptors: atrule.descriptors && dumpMapSyntax(atrule.descriptors, compact, syntaxAsAst)
+        };
+    }
+
+    return result;
+}
+
+function valueHasVar(tokens) {
+    for (let i = 0; i < tokens.length; i++) {
+        if (tokens[i].value.toLowerCase() === 'var(') {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+function buildMatchResult(matched, error, iterations) {
+    return {
+        matched,
+        iterations,
+        error,
+        ...trace
+    };
+}
+
+function matchSyntax(lexer, syntax, value, useCssWideKeywords) {
+    const tokens = prepareTokens(value, lexer.syntax);
+    let result;
+
+    if (valueHasVar(tokens)) {
+        return buildMatchResult(null, new Error('Matching for a tree with var() is not supported'));
+    }
+
+    if (useCssWideKeywords) {
+        result = matchAsTree(tokens, lexer.cssWideKeywordsSyntax, lexer);
+    }
+
+    if (!useCssWideKeywords || !result.match) {
+        result = matchAsTree(tokens, syntax.match, lexer);
+        if (!result.match) {
+            return buildMatchResult(
+                null,
+                new SyntaxMatchError(result.reason, syntax.syntax, value, result),
+                result.iterations
+            );
+        }
+    }
+
+    return buildMatchResult(result.match, null, result.iterations);
+}
+
+export class Lexer {
+    constructor(config, syntax, structure) {
+        this.cssWideKeywordsSyntax = cssWideKeywordsSyntax;
+        this.syntax = syntax;
+        this.generic = false;
+        this.atrules = Object.create(null);
+        this.properties = Object.create(null);
+        this.types = Object.create(null);
+        this.structure = structure || getStructureFromConfig(config);
+
+        if (config) {
+            if (config.types) {
+                for (const name in config.types) {
+                    this.addType_(name, config.types[name]);
+                }
+            }
+
+            if (config.generic) {
+                this.generic = true;
+                for (const name in generic) {
+                    this.addType_(name, generic[name]);
+                }
+            }
+
+            if (config.atrules) {
+                for (const name in config.atrules) {
+                    this.addAtrule_(name, config.atrules[name]);
+                }
+            }
+
+            if (config.properties) {
+                for (const name in config.properties) {
+                    this.addProperty_(name, config.properties[name]);
+                }
+            }
+        }
+    }
+
+    checkStructure(ast) {
+        function collectWarning(node, message) {
+            warns.push({ node, message });
+        }
+
+        const structure = this.structure;
+        const warns = [];
+
+        this.syntax.walk(ast, function(node) {
+            if (structure.hasOwnProperty(node.type)) {
+                structure[node.type].check(node, collectWarning);
+            } else {
+                collectWarning(node, 'Unknown node type `' + node.type + '`');
+            }
+        });
+
+        return warns.length ? warns : false;
+    }
+
+    createDescriptor(syntax, type, name, parent = null) {
+        const ref = {
+            type,
+            name
+        };
+        const descriptor = {
+            type,
+            name,
+            parent,
+            serializable: typeof syntax === 'string' || (syntax && typeof syntax.type === 'string'),
+            syntax: null,
+            match: null
+        };
+
+        if (typeof syntax === 'function') {
+            descriptor.match = buildMatchGraph(syntax, ref);
+        } else {
+            if (typeof syntax === 'string') {
+                // lazy parsing on first access
+                Object.defineProperty(descriptor, 'syntax', {
+                    get() {
+                        Object.defineProperty(descriptor, 'syntax', {
+                            value: parse(syntax)
+                        });
+
+                        return descriptor.syntax;
+                    }
+                });
+            } else {
+                descriptor.syntax = syntax;
+            }
+
+            // lazy graph build on first access
+            Object.defineProperty(descriptor, 'match', {
+                get() {
+                    Object.defineProperty(descriptor, 'match', {
+                        value: buildMatchGraph(descriptor.syntax, ref)
+                    });
+
+                    return descriptor.match;
+                }
+            });
+        }
+
+        return descriptor;
+    }
+    addAtrule_(name, syntax) {
+        if (!syntax) {
+            return;
+        }
+
+        this.atrules[name] = {
+            type: 'Atrule',
+            name: name,
+            prelude: syntax.prelude ? this.createDescriptor(syntax.prelude, 'AtrulePrelude', name) : null,
+            descriptors: syntax.descriptors
+                ? Object.keys(syntax.descriptors).reduce(
+                    (map, descName) => {
+                        map[descName] = this.createDescriptor(syntax.descriptors[descName], 'AtruleDescriptor', descName, name);
+                        return map;
+                    },
+                    Object.create(null)
+                )
+                : null
+        };
+    }
+    addProperty_(name, syntax) {
+        if (!syntax) {
+            return;
+        }
+
+        this.properties[name] = this.createDescriptor(syntax, 'Property', name);
+    }
+    addType_(name, syntax) {
+        if (!syntax) {
+            return;
+        }
+
+        this.types[name] = this.createDescriptor(syntax, 'Type', name);
+    }
+
+    checkAtruleName(atruleName) {
+        if (!this.getAtrule(atruleName)) {
+            return new SyntaxReferenceError('Unknown at-rule', '@' + atruleName);
+        }
+    }
+    checkAtrulePrelude(atruleName, prelude) {
+        const error = this.checkAtruleName(atruleName);
+
+        if (error) {
+            return error;
+        }
+
+        const atrule = this.getAtrule(atruleName);
+
+        if (!atrule.prelude && prelude) {
+            return new SyntaxError('At-rule `@' + atruleName + '` should not contain a prelude');
+        }
+
+        if (atrule.prelude && !prelude) {
+            if (!matchSyntax(this, atrule.prelude, '', false).matched) {
+                return new SyntaxError('At-rule `@' + atruleName + '` should contain a prelude');
+            }
+        }
+    }
+    checkAtruleDescriptorName(atruleName, descriptorName) {
+        const error = this.checkAtruleName(atruleName);
+
+        if (error) {
+            return error;
+        }
+
+        const atrule = this.getAtrule(atruleName);
+        const descriptor = names.keyword(descriptorName);
+
+        if (!atrule.descriptors) {
+            return new SyntaxError('At-rule `@' + atruleName + '` has no known descriptors');
+        }
+
+        if (!atrule.descriptors[descriptor.name] &&
+            !atrule.descriptors[descriptor.basename]) {
+            return new SyntaxReferenceError('Unknown at-rule descriptor', descriptorName);
+        }
+    }
+    checkPropertyName(propertyName) {
+        if (!this.getProperty(propertyName)) {
+            return new SyntaxReferenceError('Unknown property', propertyName);
+        }
+    }
+
+    matchAtrulePrelude(atruleName, prelude) {
+        const error = this.checkAtrulePrelude(atruleName, prelude);
+
+        if (error) {
+            return buildMatchResult(null, error);
+        }
+
+        const atrule = this.getAtrule(atruleName);
+
+        if (!atrule.prelude) {
+            return buildMatchResult(null, null);
+        }
+
+        return matchSyntax(this, atrule.prelude, prelude || '', false);
+    }
+    matchAtruleDescriptor(atruleName, descriptorName, value) {
+        const error = this.checkAtruleDescriptorName(atruleName, descriptorName);
+
+        if (error) {
+            return buildMatchResult(null, error);
+        }
+
+        const atrule = this.getAtrule(atruleName);
+        const descriptor = names.keyword(descriptorName);
+
+        return matchSyntax(this, atrule.descriptors[descriptor.name] || atrule.descriptors[descriptor.basename], value, false);
+    }
+    matchDeclaration(node) {
+        if (node.type !== 'Declaration') {
+            return buildMatchResult(null, new Error('Not a Declaration node'));
+        }
+
+        return this.matchProperty(node.property, node.value);
+    }
+    matchProperty(propertyName, value) {
+        // don't match syntax for a custom property at the moment
+        if (names.property(propertyName).custom) {
+            return buildMatchResult(null, new Error('Lexer matching doesn\'t applicable for custom properties'));
+        }
+
+        const error = this.checkPropertyName(propertyName);
+
+        if (error) {
+            return buildMatchResult(null, error);
+        }
+
+        return matchSyntax(this, this.getProperty(propertyName), value, true);
+    }
+    matchType(typeName, value) {
+        const typeSyntax = this.getType(typeName);
+
+        if (!typeSyntax) {
+            return buildMatchResult(null, new SyntaxReferenceError('Unknown type', typeName));
+        }
+
+        return matchSyntax(this, typeSyntax, value, false);
+    }
+    match(syntax, value) {
+        if (typeof syntax !== 'string' && (!syntax || !syntax.type)) {
+            return buildMatchResult(null, new SyntaxReferenceError('Bad syntax'));
+        }
+
+        if (typeof syntax === 'string' || !syntax.match) {
+            syntax = this.createDescriptor(syntax, 'Type', 'anonymous');
+        }
+
+        return matchSyntax(this, syntax, value, false);
+    }
+
+    findValueFragments(propertyName, value, type, name) {
+        return matchFragments(this, value, this.matchProperty(propertyName, value), type, name);
+    }
+    findDeclarationValueFragments(declaration, type, name) {
+        return matchFragments(this, declaration.value, this.matchDeclaration(declaration), type, name);
+    }
+    findAllFragments(ast, type, name) {
+        const result = [];
+
+        this.syntax.walk(ast, {
+            visit: 'Declaration',
+            enter: (declaration) => {
+                result.push.apply(result, this.findDeclarationValueFragments(declaration, type, name));
+            }
+        });
+
+        return result;
+    }
+
+    getAtrule(atruleName, fallbackBasename = true) {
+        const atrule = names.keyword(atruleName);
+        const atruleEntry = atrule.vendor && fallbackBasename
+            ? this.atrules[atrule.name] || this.atrules[atrule.basename]
+            : this.atrules[atrule.name];
+
+        return atruleEntry || null;
+    }
+    getAtrulePrelude(atruleName, fallbackBasename = true) {
+        const atrule = this.getAtrule(atruleName, fallbackBasename);
+
+        return atrule && atrule.prelude || null;
+    }
+    getAtruleDescriptor(atruleName, name) {
+        return this.atrules.hasOwnProperty(atruleName) && this.atrules.declarators
+            ? this.atrules[atruleName].declarators[name] || null
+            : null;
+    }
+    getProperty(propertyName, fallbackBasename = true) {
+        const property = names.property(propertyName);
+        const propertyEntry = property.vendor && fallbackBasename
+            ? this.properties[property.name] || this.properties[property.basename]
+            : this.properties[property.name];
+
+        return propertyEntry || null;
+    }
+    getType(name) {
+        return hasOwnProperty.call(this.types, name) ? this.types[name] : null;
+    }
+
+    validate() {
+        function validate(syntax, name, broken, descriptor) {
+            if (broken.has(name)) {
+                return broken.get(name);
+            }
+
+            broken.set(name, false);
+            if (descriptor.syntax !== null) {
+                walk(descriptor.syntax, function(node) {
+                    if (node.type !== 'Type' && node.type !== 'Property') {
+                        return;
+                    }
+
+                    const map = node.type === 'Type' ? syntax.types : syntax.properties;
+                    const brokenMap = node.type === 'Type' ? brokenTypes : brokenProperties;
+
+                    if (!hasOwnProperty.call(map, node.name) || validate(syntax, node.name, brokenMap, map[node.name])) {
+                        broken.set(name, true);
+                    }
+                }, this);
+            }
+        }
+
+        let brokenTypes = new Map();
+        let brokenProperties = new Map();
+
+        for (const key in this.types) {
+            validate(this, key, brokenTypes, this.types[key]);
+        }
+
+        for (const key in this.properties) {
+            validate(this, key, brokenProperties, this.properties[key]);
+        }
+
+        brokenTypes = [...brokenTypes.keys()].filter(name => brokenTypes.get(name));
+        brokenProperties = [...brokenProperties.keys()].filter(name => brokenProperties.get(name));
+
+        if (brokenTypes.length || brokenProperties.length) {
+            return {
+                types: brokenTypes,
+                properties: brokenProperties
+            };
+        }
+
+        return null;
+    }
+    dump(syntaxAsAst, pretty) {
+        return {
+            generic: this.generic,
+            types: dumpMapSyntax(this.types, !pretty, syntaxAsAst),
+            properties: dumpMapSyntax(this.properties, !pretty, syntaxAsAst),
+            atrules: dumpAtruleMapSyntax(this.atrules, !pretty, syntaxAsAst)
+        };
+    }
+    toString() {
+        return JSON.stringify(this.dump());
+    }
+};

node_modules/css-tree/lib/lexer/error.js

@@ -0,0 +1,123 @@
+import { createCustomError } from '../utils/create-custom-error.js';
+import { generate } from '../definition-syntax/generate.js';
+
+const defaultLoc = { offset: 0, line: 1, column: 1 };
+
+function locateMismatch(matchResult, node) {
+    const tokens = matchResult.tokens;
+    const longestMatch = matchResult.longestMatch;
+    const mismatchNode = longestMatch < tokens.length ? tokens[longestMatch].node || null : null;
+    const badNode = mismatchNode !== node ? mismatchNode : null;
+    let mismatchOffset = 0;
+    let mismatchLength = 0;
+    let entries = 0;
+    let css = '';
+    let start;
+    let end;
+
+    for (let i = 0; i < tokens.length; i++) {
+        const token = tokens[i].value;
+
+        if (i === longestMatch) {
+            mismatchLength = token.length;
+            mismatchOffset = css.length;
+        }
+
+        if (badNode !== null && tokens[i].node === badNode) {
+            if (i <= longestMatch) {
+                entries++;
+            } else {
+                entries = 0;
+            }
+        }
+
+        css += token;
+    }
+
+    if (longestMatch === tokens.length || entries > 1) { // last
+        start = fromLoc(badNode || node, 'end') || buildLoc(defaultLoc, css);
+        end = buildLoc(start);
+    } else {
+        start = fromLoc(badNode, 'start') ||
+            buildLoc(fromLoc(node, 'start') || defaultLoc, css.slice(0, mismatchOffset));
+        end = fromLoc(badNode, 'end') ||
+            buildLoc(start, css.substr(mismatchOffset, mismatchLength));
+    }
+
+    return {
+        css,
+        mismatchOffset,
+        mismatchLength,
+        start,
+        end
+    };
+}
+
+function fromLoc(node, point) {
+    const value = node && node.loc && node.loc[point];
+
+    if (value) {
+        return 'line' in value ? buildLoc(value) : value;
+    }
+
+    return null;
+}
+
+function buildLoc({ offset, line, column }, extra) {
+    const loc = {
+        offset,
+        line,
+        column
+    };
+
+    if (extra) {
+        const lines = extra.split(/\n|\r\n?|\f/);
+
+        loc.offset += extra.length;
+        loc.line += lines.length - 1;
+        loc.column = lines.length === 1 ? loc.column + extra.length : lines.pop().length + 1;
+    }
+
+    return loc;
+}
+
+export const SyntaxReferenceError = function(type, referenceName) {
+    const error = createCustomError(
+        'SyntaxReferenceError',
+        type + (referenceName ? ' `' + referenceName + '`' : '')
+    );
+
+    error.reference = referenceName;
+
+    return error;
+};
+
+export const SyntaxMatchError = function(message, syntax, node, matchResult) {
+    const error = createCustomError('SyntaxMatchError', message);
+    const {
+        css,
+        mismatchOffset,
+        mismatchLength,
+        start,
+        end
+    } = locateMismatch(matchResult, node);
+
+    error.rawMessage = message;
+    error.syntax = syntax ? generate(syntax) : '<generic>';
+    error.css = css;
+    error.mismatchOffset = mismatchOffset;
+    error.mismatchLength = mismatchLength;
+    error.message = message + '\n' +
+        '  syntax: ' + error.syntax + '\n' +
+        '   value: ' + (css || '<empty string>') + '\n' +
+        '  --------' + new Array(error.mismatchOffset + 1).join('-') + '^';
+
+    Object.assign(error, start);
+    error.loc = {
+        source: (node && node.loc && node.loc.source) || '<unknown>',
+        start,
+        end
+    };
+
+    return error;
+};

node_modules/css-tree/lib/lexer/generic-an-plus-b.js

@@ -0,0 +1,238 @@
+import {
+    isDigit,
+    cmpChar,
+    Delim,
+    WhiteSpace,
+    Comment,
+    Ident,
+    Number as NumberToken,
+    Dimension
+} from '../tokenizer/index.js';
+
+const PLUSSIGN = 0x002B;    // U+002B PLUS SIGN (+)
+const HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
+const N = 0x006E;           // U+006E LATIN SMALL LETTER N (n)
+const DISALLOW_SIGN = true;
+const ALLOW_SIGN = false;
+
+function isDelim(token, code) {
+    return token !== null && token.type === Delim && token.value.charCodeAt(0) === code;
+}
+
+function skipSC(token, offset, getNextToken) {
+    while (token !== null && (token.type === WhiteSpace || token.type === Comment)) {
+        token = getNextToken(++offset);
+    }
+
+    return offset;
+}
+
+function checkInteger(token, valueOffset, disallowSign, offset) {
+    if (!token) {
+        return 0;
+    }
+
+    const code = token.value.charCodeAt(valueOffset);
+
+    if (code === PLUSSIGN || code === HYPHENMINUS) {
+        if (disallowSign) {
+            // Number sign is not allowed
+            return 0;
+        }
+        valueOffset++;
+    }
+
+    for (; valueOffset < token.value.length; valueOffset++) {
+        if (!isDigit(token.value.charCodeAt(valueOffset))) {
+            // Integer is expected
+            return 0;
+        }
+    }
+
+    return offset + 1;
+}
+
+// ... <signed-integer>
+// ... ['+' | '-'] <signless-integer>
+function consumeB(token, offset_, getNextToken) {
+    let sign = false;
+    let offset = skipSC(token, offset_, getNextToken);
+
+    token = getNextToken(offset);
+
+    if (token === null) {
+        return offset_;
+    }
+
+    if (token.type !== NumberToken) {
+        if (isDelim(token, PLUSSIGN) || isDelim(token, HYPHENMINUS)) {
+            sign = true;
+            offset = skipSC(getNextToken(++offset), offset, getNextToken);
+            token = getNextToken(offset);
+
+            if (token === null || token.type !== NumberToken) {
+                return 0;
+            }
+        } else {
+            return offset_;
+        }
+    }
+
+    if (!sign) {
+        const code = token.value.charCodeAt(0);
+        if (code !== PLUSSIGN && code !== HYPHENMINUS) {
+            // Number sign is expected
+            return 0;
+        }
+    }
+
+    return checkInteger(token, sign ? 0 : 1, sign, offset);
+}
+
+// An+B microsyntax https://www.w3.org/TR/css-syntax-3/#anb
+export default function anPlusB(token, getNextToken) {
+    /* eslint-disable brace-style*/
+    let offset = 0;
+
+    if (!token) {
+        return 0;
+    }
+
+    // <integer>
+    if (token.type === NumberToken) {
+        return checkInteger(token, 0, ALLOW_SIGN, offset); // b
+    }
+
+    // -n
+    // -n <signed-integer>
+    // -n ['+' | '-'] <signless-integer>
+    // -n- <signless-integer>
+    // <dashndashdigit-ident>
+    else if (token.type === Ident && token.value.charCodeAt(0) === HYPHENMINUS) {
+        // expect 1st char is N
+        if (!cmpChar(token.value, 1, N)) {
+            return 0;
+        }
+
+        switch (token.value.length) {
+            // -n
+            // -n <signed-integer>
+            // -n ['+' | '-'] <signless-integer>
+            case 2:
+                return consumeB(getNextToken(++offset), offset, getNextToken);
+
+            // -n- <signless-integer>
+            case 3:
+                if (token.value.charCodeAt(2) !== HYPHENMINUS) {
+                    return 0;
+                }
+
+                offset = skipSC(getNextToken(++offset), offset, getNextToken);
+                token = getNextToken(offset);
+
+                return checkInteger(token, 0, DISALLOW_SIGN, offset);
+
+            // <dashndashdigit-ident>
+            default:
+                if (token.value.charCodeAt(2) !== HYPHENMINUS) {
+                    return 0;
+                }
+
+                return checkInteger(token, 3, DISALLOW_SIGN, offset);
+        }
+    }
+
+    // '+'? n
+    // '+'? n <signed-integer>
+    // '+'? n ['+' | '-'] <signless-integer>
+    // '+'? n- <signless-integer>
+    // '+'? <ndashdigit-ident>
+    else if (token.type === Ident || (isDelim(token, PLUSSIGN) && getNextToken(offset + 1).type === Ident)) {
+        // just ignore a plus
+        if (token.type !== Ident) {
+            token = getNextToken(++offset);
+        }
+
+        if (token === null || !cmpChar(token.value, 0, N)) {
+            return 0;
+        }
+
+        switch (token.value.length) {
+            // '+'? n
+            // '+'? n <signed-integer>
+            // '+'? n ['+' | '-'] <signless-integer>
+            case 1:
+                return consumeB(getNextToken(++offset), offset, getNextToken);
+
+            // '+'? n- <signless-integer>
+            case 2:
+                if (token.value.charCodeAt(1) !== HYPHENMINUS) {
+                    return 0;
+                }
+
+                offset = skipSC(getNextToken(++offset), offset, getNextToken);
+                token = getNextToken(offset);
+
+                return checkInteger(token, 0, DISALLOW_SIGN, offset);
+
+            // '+'? <ndashdigit-ident>
+            default:
+                if (token.value.charCodeAt(1) !== HYPHENMINUS) {
+                    return 0;
+                }
+
+                return checkInteger(token, 2, DISALLOW_SIGN, offset);
+        }
+    }
+
+    // <ndashdigit-dimension>
+    // <ndash-dimension> <signless-integer>
+    // <n-dimension>
+    // <n-dimension> <signed-integer>
+    // <n-dimension> ['+' | '-'] <signless-integer>
+    else if (token.type === Dimension) {
+        let code = token.value.charCodeAt(0);
+        let sign = code === PLUSSIGN || code === HYPHENMINUS ? 1 : 0;
+        let i = sign;
+
+        for (; i < token.value.length; i++) {
+            if (!isDigit(token.value.charCodeAt(i))) {
+                break;
+            }
+        }
+
+        if (i === sign) {
+            // Integer is expected
+            return 0;
+        }
+
+        if (!cmpChar(token.value, i, N)) {
+            return 0;
+        }
+
+        // <n-dimension>
+        // <n-dimension> <signed-integer>
+        // <n-dimension> ['+' | '-'] <signless-integer>
+        if (i + 1 === token.value.length) {
+            return consumeB(getNextToken(++offset), offset, getNextToken);
+        } else {
+            if (token.value.charCodeAt(i + 1) !== HYPHENMINUS) {
+                return 0;
+            }
+
+            // <ndash-dimension> <signless-integer>
+            if (i + 2 === token.value.length) {
+                offset = skipSC(getNextToken(++offset), offset, getNextToken);
+                token = getNextToken(offset);
+
+                return checkInteger(token, 0, DISALLOW_SIGN, offset);
+            }
+            // <ndashdigit-dimension>
+            else {
+                return checkInteger(token, i + 2, DISALLOW_SIGN, offset);
+            }
+        }
+    }
+
+    return 0;
+};

node_modules/css-tree/lib/lexer/generic-const.js

@@ -0,0 +1,8 @@
+// https://drafts.csswg.org/css-cascade-5/
+export const cssWideKeywords = [
+    'initial',
+    'inherit',
+    'unset',
+    'revert',
+    'revert-layer'
+];

node_modules/css-tree/lib/lexer/generic-urange.js

@@ -0,0 +1,151 @@
+import {
+    isHexDigit,
+    cmpChar,
+    Ident,
+    Delim,
+    Number as NumberToken,
+    Dimension
+} from '../tokenizer/index.js';
+
+const PLUSSIGN = 0x002B;     // U+002B PLUS SIGN (+)
+const HYPHENMINUS = 0x002D;  // U+002D HYPHEN-MINUS (-)
+const QUESTIONMARK = 0x003F; // U+003F QUESTION MARK (?)
+const U = 0x0075;            // U+0075 LATIN SMALL LETTER U (u)
+
+function isDelim(token, code) {
+    return token !== null && token.type === Delim && token.value.charCodeAt(0) === code;
+}
+
+function startsWith(token, code) {
+    return token.value.charCodeAt(0) === code;
+}
+
+function hexSequence(token, offset, allowDash) {
+    let hexlen = 0;
+
+    for (let pos = offset; pos < token.value.length; pos++) {
+        const code = token.value.charCodeAt(pos);
+
+        if (code === HYPHENMINUS && allowDash && hexlen !== 0) {
+            hexSequence(token, offset + hexlen + 1, false);
+            return 6; // dissallow following question marks
+        }
+
+        if (!isHexDigit(code)) {
+            return 0; // not a hex digit
+        }
+
+        if (++hexlen > 6) {
+            return 0; // too many hex digits
+        };
+    }
+
+    return hexlen;
+}
+
+function withQuestionMarkSequence(consumed, length, getNextToken) {
+    if (!consumed) {
+        return 0; // nothing consumed
+    }
+
+    while (isDelim(getNextToken(length), QUESTIONMARK)) {
+        if (++consumed > 6) {
+            return 0; // too many question marks
+        }
+
+        length++;
+    }
+
+    return length;
+}
+
+// https://drafts.csswg.org/css-syntax/#urange
+// Informally, the <urange> production has three forms:
+// U+0001
+//      Defines a range consisting of a single code point, in this case the code point "1".
+// U+0001-00ff
+//      Defines a range of codepoints between the first and the second value, in this case
+//      the range between "1" and "ff" (255 in decimal) inclusive.
+// U+00??
+//      Defines a range of codepoints where the "?" characters range over all hex digits,
+//      in this case defining the same as the value U+0000-00ff.
+// In each form, a maximum of 6 digits is allowed for each hexadecimal number (if you treat "?" as a hexadecimal digit).
+//
+// <urange> =
+//   u '+' <ident-token> '?'* |
+//   u <dimension-token> '?'* |
+//   u <number-token> '?'* |
+//   u <number-token> <dimension-token> |
+//   u <number-token> <number-token> |
+//   u '+' '?'+
+export default function urange(token, getNextToken) {
+    let length = 0;
+
+    // should start with `u` or `U`
+    if (token === null || token.type !== Ident || !cmpChar(token.value, 0, U)) {
+        return 0;
+    }
+
+    token = getNextToken(++length);
+    if (token === null) {
+        return 0;
+    }
+
+    // u '+' <ident-token> '?'*
+    // u '+' '?'+
+    if (isDelim(token, PLUSSIGN)) {
+        token = getNextToken(++length);
+        if (token === null) {
+            return 0;
+        }
+
+        if (token.type === Ident) {
+            // u '+' <ident-token> '?'*
+            return withQuestionMarkSequence(hexSequence(token, 0, true), ++length, getNextToken);
+        }
+
+        if (isDelim(token, QUESTIONMARK)) {
+            // u '+' '?'+
+            return withQuestionMarkSequence(1, ++length, getNextToken);
+        }
+
+        // Hex digit or question mark is expected
+        return 0;
+    }
+
+    // u <number-token> '?'*
+    // u <number-token> <dimension-token>
+    // u <number-token> <number-token>
+    if (token.type === NumberToken) {
+        const consumedHexLength = hexSequence(token, 1, true);
+        if (consumedHexLength === 0) {
+            return 0;
+        }
+
+        token = getNextToken(++length);
+        if (token === null) {
+            // u <number-token> <eof>
+            return length;
+        }
+
+        if (token.type === Dimension || token.type === NumberToken) {
+            // u <number-token> <dimension-token>
+            // u <number-token> <number-token>
+            if (!startsWith(token, HYPHENMINUS) || !hexSequence(token, 1, false)) {
+                return 0;
+            }
+
+            return length + 1;
+        }
+
+        // u <number-token> '?'*
+        return withQuestionMarkSequence(consumedHexLength, length, getNextToken);
+    }
+
+    // u <dimension-token> '?'*
+    if (token.type === Dimension) {
+        return withQuestionMarkSequence(hexSequence(token, 1, true), ++length, getNextToken);
+    }
+
+    return 0;
+};

node_modules/css-tree/lib/lexer/generic.js

@@ -0,0 +1,598 @@
+import { cssWideKeywords } from './generic-const.js';
+import anPlusB from './generic-an-plus-b.js';
+import urange from './generic-urange.js';
+import {
+    isIdentifierStart,
+    isHexDigit,
+    isDigit,
+    cmpStr,
+    consumeNumber,
+
+    Ident,
+    Function as FunctionToken,
+    AtKeyword,
+    Hash,
+    String as StringToken,
+    BadString,
+    Url,
+    BadUrl,
+    Delim,
+    Number as NumberToken,
+    Percentage,
+    Dimension,
+    WhiteSpace,
+    CDO,
+    CDC,
+    Colon,
+    Semicolon,
+    Comma,
+    LeftSquareBracket,
+    RightSquareBracket,
+    LeftParenthesis,
+    RightParenthesis,
+    LeftCurlyBracket,
+    RightCurlyBracket
+} from '../tokenizer/index.js';
+
+const calcFunctionNames = ['calc(', '-moz-calc(', '-webkit-calc('];
+const balancePair = new Map([
+    [FunctionToken, RightParenthesis],
+    [LeftParenthesis, RightParenthesis],
+    [LeftSquareBracket, RightSquareBracket],
+    [LeftCurlyBracket, RightCurlyBracket]
+]);
+
+// units
+const LENGTH = [
+    // absolute length units https://www.w3.org/TR/css-values-3/#lengths
+    'cm', 'mm', 'q', 'in', 'pt', 'pc', 'px',
+    // font-relative length units https://drafts.csswg.org/css-values-4/#font-relative-lengths
+    'em', 'rem',
+    'ex', 'rex',
+    'cap', 'rcap',
+    'ch', 'rch',
+    'ic', 'ric',
+    'lh', 'rlh',
+    // viewport-percentage lengths https://drafts.csswg.org/css-values-4/#viewport-relative-lengths
+    'vw', 'svw', 'lvw', 'dvw',
+    'vh', 'svh', 'lvh', 'dvh',
+    'vi', 'svi', 'lvi', 'dvi',
+    'vb', 'svb', 'lvb', 'dvb',
+    'vmin', 'svmin', 'lvmin', 'dvmin',
+    'vmax', 'svmax', 'lvmax', 'dvmax',
+    // container relative lengths https://drafts.csswg.org/css-contain-3/#container-lengths
+    'cqw', 'cqh', 'cqi', 'cqb', 'cqmin', 'cqmax'
+];
+const ANGLE = ['deg', 'grad', 'rad', 'turn']; // https://www.w3.org/TR/css-values-3/#angles
+const TIME = ['s', 'ms'];                     // https://www.w3.org/TR/css-values-3/#time
+const FREQUENCY = ['hz', 'khz'];              // https://www.w3.org/TR/css-values-3/#frequency
+const RESOLUTION = ['dpi', 'dpcm', 'dppx', 'x']; // https://www.w3.org/TR/css-values-3/#resolution
+const FLEX = ['fr'];                          // https://drafts.csswg.org/css-grid/#fr-unit
+const DECIBEL = ['db'];                       // https://www.w3.org/TR/css3-speech/#mixing-props-voice-volume
+const SEMITONES = ['st'];                     // https://www.w3.org/TR/css3-speech/#voice-props-voice-pitch
+
+// safe char code getter
+function charCodeAt(str, index) {
+    return index < str.length ? str.charCodeAt(index) : 0;
+}
+
+function eqStr(actual, expected) {
+    return cmpStr(actual, 0, actual.length, expected);
+}
+
+function eqStrAny(actual, expected) {
+    for (let i = 0; i < expected.length; i++) {
+        if (eqStr(actual, expected[i])) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+// IE postfix hack, i.e. 123\0 or 123px\9
+function isPostfixIeHack(str, offset) {
+    if (offset !== str.length - 2) {
+        return false;
+    }
+
+    return (
+        charCodeAt(str, offset) === 0x005C &&  // U+005C REVERSE SOLIDUS (\)
+        isDigit(charCodeAt(str, offset + 1))
+    );
+}
+
+function outOfRange(opts, value, numEnd) {
+    if (opts && opts.type === 'Range') {
+        const num = Number(
+            numEnd !== undefined && numEnd !== value.length
+                ? value.substr(0, numEnd)
+                : value
+        );
+
+        if (isNaN(num)) {
+            return true;
+        }
+
+        // FIXME: when opts.min is a string it's a dimension, skip a range validation
+        // for now since it requires a type covertation which is not implmented yet
+        if (opts.min !== null && num < opts.min && typeof opts.min !== 'string') {
+            return true;
+        }
+
+        // FIXME: when opts.max is a string it's a dimension, skip a range validation
+        // for now since it requires a type covertation which is not implmented yet
+        if (opts.max !== null && num > opts.max && typeof opts.max !== 'string') {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+function consumeFunction(token, getNextToken) {
+    let balanceCloseType = 0;
+    let balanceStash = [];
+    let length = 0;
+
+    // balanced token consuming
+    scan:
+    do {
+        switch (token.type) {
+            case RightCurlyBracket:
+            case RightParenthesis:
+            case RightSquareBracket:
+                if (token.type !== balanceCloseType) {
+                    break scan;
+                }
+
+                balanceCloseType = balanceStash.pop();
+
+                if (balanceStash.length === 0) {
+                    length++;
+                    break scan;
+                }
+
+                break;
+
+            case FunctionToken:
+            case LeftParenthesis:
+            case LeftSquareBracket:
+            case LeftCurlyBracket:
+                balanceStash.push(balanceCloseType);
+                balanceCloseType = balancePair.get(token.type);
+                break;
+        }
+
+        length++;
+    } while (token = getNextToken(length));
+
+    return length;
+}
+
+// TODO: implement
+// can be used wherever <length>, <frequency>, <angle>, <time>, <percentage>, <number>, or <integer> values are allowed
+// https://drafts.csswg.org/css-values/#calc-notation
+function calc(next) {
+    return function(token, getNextToken, opts) {
+        if (token === null) {
+            return 0;
+        }
+
+        if (token.type === FunctionToken && eqStrAny(token.value, calcFunctionNames)) {
+            return consumeFunction(token, getNextToken);
+        }
+
+        return next(token, getNextToken, opts);
+    };
+}
+
+function tokenType(expectedTokenType) {
+    return function(token) {
+        if (token === null || token.type !== expectedTokenType) {
+            return 0;
+        }
+
+        return 1;
+    };
+}
+
+// =========================
+// Complex types
+//
+
+// https://drafts.csswg.org/css-values-4/#custom-idents
+// 4.2. Author-defined Identifiers: the <custom-ident> type
+// Some properties accept arbitrary author-defined identifiers as a component value.
+// This generic data type is denoted by <custom-ident>, and represents any valid CSS identifier
+// that would not be misinterpreted as a pre-defined keyword in that property’s value definition.
+//
+// See also: https://developer.mozilla.org/en-US/docs/Web/CSS/custom-ident
+function customIdent(token) {
+    if (token === null || token.type !== Ident) {
+        return 0;
+    }
+
+    const name = token.value.toLowerCase();
+
+    // The CSS-wide keywords are not valid <custom-ident>s
+    if (eqStrAny(name, cssWideKeywords)) {
+        return 0;
+    }
+
+    // The default keyword is reserved and is also not a valid <custom-ident>
+    if (eqStr(name, 'default')) {
+        return 0;
+    }
+
+    // TODO: ignore property specific keywords (as described https://developer.mozilla.org/en-US/docs/Web/CSS/custom-ident)
+    // Specifications using <custom-ident> must specify clearly what other keywords
+    // are excluded from <custom-ident>, if any—for example by saying that any pre-defined keywords
+    // in that property’s value definition are excluded. Excluded keywords are excluded
+    // in all ASCII case permutations.
+
+    return 1;
+}
+
+// https://drafts.csswg.org/css-variables/#typedef-custom-property-name
+// A custom property is any property whose name starts with two dashes (U+002D HYPHEN-MINUS), like --foo.
+// The <custom-property-name> production corresponds to this: it’s defined as any valid identifier
+// that starts with two dashes, except -- itself, which is reserved for future use by CSS.
+// NOTE: Current implementation treat `--` as a valid name since most (all?) major browsers treat it as valid.
+function customPropertyName(token) {
+    // ... defined as any valid identifier
+    if (token === null || token.type !== Ident) {
+        return 0;
+    }
+
+    // ... that starts with two dashes (U+002D HYPHEN-MINUS)
+    if (charCodeAt(token.value, 0) !== 0x002D || charCodeAt(token.value, 1) !== 0x002D) {
+        return 0;
+    }
+
+    return 1;
+}
+
+// https://drafts.csswg.org/css-color-4/#hex-notation
+// The syntax of a <hex-color> is a <hash-token> token whose value consists of 3, 4, 6, or 8 hexadecimal digits.
+// In other words, a hex color is written as a hash character, "#", followed by some number of digits 0-9 or
+// letters a-f (the case of the letters doesn’t matter - #00ff00 is identical to #00FF00).
+function hexColor(token) {
+    if (token === null || token.type !== Hash) {
+        return 0;
+    }
+
+    const length = token.value.length;
+
+    // valid values (length): #rgb (4), #rgba (5), #rrggbb (7), #rrggbbaa (9)
+    if (length !== 4 && length !== 5 && length !== 7 && length !== 9) {
+        return 0;
+    }
+
+    for (let i = 1; i < length; i++) {
+        if (!isHexDigit(charCodeAt(token.value, i))) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+function idSelector(token) {
+    if (token === null || token.type !== Hash) {
+        return 0;
+    }
+
+    if (!isIdentifierStart(charCodeAt(token.value, 1), charCodeAt(token.value, 2), charCodeAt(token.value, 3))) {
+        return 0;
+    }
+
+    return 1;
+}
+
+// https://drafts.csswg.org/css-syntax/#any-value
+// It represents the entirety of what a valid declaration can have as its value.
+function declarationValue(token, getNextToken) {
+    if (!token) {
+        return 0;
+    }
+
+    let balanceCloseType = 0;
+    let balanceStash = [];
+    let length = 0;
+
+    // The <declaration-value> production matches any sequence of one or more tokens,
+    // so long as the sequence does not contain ...
+    scan:
+    do {
+        switch (token.type) {
+            // ... <bad-string-token>, <bad-url-token>,
+            case BadString:
+            case BadUrl:
+                break scan;
+
+            // ... unmatched <)-token>, <]-token>, or <}-token>,
+            case RightCurlyBracket:
+            case RightParenthesis:
+            case RightSquareBracket:
+                if (token.type !== balanceCloseType) {
+                    break scan;
+                }
+
+                balanceCloseType = balanceStash.pop();
+                break;
+
+            // ... or top-level <semicolon-token> tokens
+            case Semicolon:
+                if (balanceCloseType === 0) {
+                    break scan;
+                }
+
+                break;
+
+            // ... or <delim-token> tokens with a value of "!"
+            case Delim:
+                if (balanceCloseType === 0 && token.value === '!') {
+                    break scan;
+                }
+
+                break;
+
+            case FunctionToken:
+            case LeftParenthesis:
+            case LeftSquareBracket:
+            case LeftCurlyBracket:
+                balanceStash.push(balanceCloseType);
+                balanceCloseType = balancePair.get(token.type);
+                break;
+        }
+
+        length++;
+    } while (token = getNextToken(length));
+
+    return length;
+}
+
+// https://drafts.csswg.org/css-syntax/#any-value
+// The <any-value> production is identical to <declaration-value>, but also
+// allows top-level <semicolon-token> tokens and <delim-token> tokens
+// with a value of "!". It represents the entirety of what valid CSS can be in any context.
+function anyValue(token, getNextToken) {
+    if (!token) {
+        return 0;
+    }
+
+    let balanceCloseType = 0;
+    let balanceStash = [];
+    let length = 0;
+
+    // The <any-value> production matches any sequence of one or more tokens,
+    // so long as the sequence ...
+    scan:
+    do {
+        switch (token.type) {
+            // ... does not contain <bad-string-token>, <bad-url-token>,
+            case BadString:
+            case BadUrl:
+                break scan;
+
+            // ... unmatched <)-token>, <]-token>, or <}-token>,
+            case RightCurlyBracket:
+            case RightParenthesis:
+            case RightSquareBracket:
+                if (token.type !== balanceCloseType) {
+                    break scan;
+                }
+
+                balanceCloseType = balanceStash.pop();
+                break;
+
+            case FunctionToken:
+            case LeftParenthesis:
+            case LeftSquareBracket:
+            case LeftCurlyBracket:
+                balanceStash.push(balanceCloseType);
+                balanceCloseType = balancePair.get(token.type);
+                break;
+        }
+
+        length++;
+    } while (token = getNextToken(length));
+
+    return length;
+}
+
+// =========================
+// Dimensions
+//
+
+function dimension(type) {
+    if (type) {
+        type = new Set(type);
+    }
+
+    return function(token, getNextToken, opts) {
+        if (token === null || token.type !== Dimension) {
+            return 0;
+        }
+
+        const numberEnd = consumeNumber(token.value, 0);
+
+        // check unit
+        if (type !== null) {
+            // check for IE postfix hack, i.e. 123px\0 or 123px\9
+            const reverseSolidusOffset = token.value.indexOf('\\', numberEnd);
+            const unit = reverseSolidusOffset === -1 || !isPostfixIeHack(token.value, reverseSolidusOffset)
+                ? token.value.substr(numberEnd)
+                : token.value.substring(numberEnd, reverseSolidusOffset);
+
+            if (type.has(unit.toLowerCase()) === false) {
+                return 0;
+            }
+        }
+
+        // check range if specified
+        if (outOfRange(opts, token.value, numberEnd)) {
+            return 0;
+        }
+
+        return 1;
+    };
+}
+
+// =========================
+// Percentage
+//
+
+// §5.5. Percentages: the <percentage> type
+// https://drafts.csswg.org/css-values-4/#percentages
+function percentage(token, getNextToken, opts) {
+    // ... corresponds to the <percentage-token> production
+    if (token === null || token.type !== Percentage) {
+        return 0;
+    }
+
+    // check range if specified
+    if (outOfRange(opts, token.value, token.value.length - 1)) {
+        return 0;
+    }
+
+    return 1;
+}
+
+// =========================
+// Numeric
+//
+
+// https://drafts.csswg.org/css-values-4/#numbers
+// The value <zero> represents a literal number with the value 0. Expressions that merely
+// evaluate to a <number> with the value 0 (for example, calc(0)) do not match <zero>;
+// only literal <number-token>s do.
+function zero(next) {
+    if (typeof next !== 'function') {
+        next = function() {
+            return 0;
+        };
+    }
+
+    return function(token, getNextToken, opts) {
+        if (token !== null && token.type === NumberToken) {
+            if (Number(token.value) === 0) {
+                return 1;
+            }
+        }
+
+        return next(token, getNextToken, opts);
+    };
+}
+
+// § 5.3. Real Numbers: the <number> type
+// https://drafts.csswg.org/css-values-4/#numbers
+// Number values are denoted by <number>, and represent real numbers, possibly with a fractional component.
+// ... It corresponds to the <number-token> production
+function number(token, getNextToken, opts) {
+    if (token === null) {
+        return 0;
+    }
+
+    const numberEnd = consumeNumber(token.value, 0);
+    const isNumber = numberEnd === token.value.length;
+    if (!isNumber && !isPostfixIeHack(token.value, numberEnd)) {
+        return 0;
+    }
+
+    // check range if specified
+    if (outOfRange(opts, token.value, numberEnd)) {
+        return 0;
+    }
+
+    return 1;
+}
+
+// §5.2. Integers: the <integer> type
+// https://drafts.csswg.org/css-values-4/#integers
+function integer(token, getNextToken, opts) {
+    // ... corresponds to a subset of the <number-token> production
+    if (token === null || token.type !== NumberToken) {
+        return 0;
+    }
+
+    // The first digit of an integer may be immediately preceded by `-` or `+` to indicate the integer’s sign.
+    let i = charCodeAt(token.value, 0) === 0x002B ||       // U+002B PLUS SIGN (+)
+            charCodeAt(token.value, 0) === 0x002D ? 1 : 0; // U+002D HYPHEN-MINUS (-)
+
+    // When written literally, an integer is one or more decimal digits 0 through 9 ...
+    for (; i < token.value.length; i++) {
+        if (!isDigit(charCodeAt(token.value, i))) {
+            return 0;
+        }
+    }
+
+    // check range if specified
+    if (outOfRange(opts, token.value, i)) {
+        return 0;
+    }
+
+    return 1;
+}
+
+export default {
+    // token types
+    'ident-token': tokenType(Ident),
+    'function-token': tokenType(FunctionToken),
+    'at-keyword-token': tokenType(AtKeyword),
+    'hash-token': tokenType(Hash),
+    'string-token': tokenType(StringToken),
+    'bad-string-token': tokenType(BadString),
+    'url-token': tokenType(Url),
+    'bad-url-token': tokenType(BadUrl),
+    'delim-token': tokenType(Delim),
+    'number-token': tokenType(NumberToken),
+    'percentage-token': tokenType(Percentage),
+    'dimension-token': tokenType(Dimension),
+    'whitespace-token': tokenType(WhiteSpace),
+    'CDO-token': tokenType(CDO),
+    'CDC-token': tokenType(CDC),
+    'colon-token': tokenType(Colon),
+    'semicolon-token': tokenType(Semicolon),
+    'comma-token': tokenType(Comma),
+    '[-token': tokenType(LeftSquareBracket),
+    ']-token': tokenType(RightSquareBracket),
+    '(-token': tokenType(LeftParenthesis),
+    ')-token': tokenType(RightParenthesis),
+    '{-token': tokenType(LeftCurlyBracket),
+    '}-token': tokenType(RightCurlyBracket),
+
+    // token type aliases
+    'string': tokenType(StringToken),
+    'ident': tokenType(Ident),
+
+    // complex types
+    'custom-ident': customIdent,
+    'custom-property-name': customPropertyName,
+    'hex-color': hexColor,
+    'id-selector': idSelector, // element( <id-selector> )
+    'an-plus-b': anPlusB,
+    'urange': urange,
+    'declaration-value': declarationValue,
+    'any-value': anyValue,
+
+    // dimensions
+    'dimension': calc(dimension(null)),
+    'angle': calc(dimension(ANGLE)),
+    'decibel': calc(dimension(DECIBEL)),
+    'frequency': calc(dimension(FREQUENCY)),
+    'flex': calc(dimension(FLEX)),
+    'length': calc(zero(dimension(LENGTH))),
+    'resolution': calc(dimension(RESOLUTION)),
+    'semitones': calc(dimension(SEMITONES)),
+    'time': calc(dimension(TIME)),
+
+    // percentage
+    'percentage': calc(percentage),
+
+    // numeric
+    'zero': zero(),
+    'number': calc(number),
+    'integer': calc(integer)
+};

node_modules/css-tree/lib/lexer/index.js

@@ -0,0 +1 @@
+export { Lexer } from './Lexer.js';

node_modules/css-tree/lib/lexer/match-graph.js

@@ -0,0 +1,456 @@
+import { parse } from '../definition-syntax/parse.js';
+
+export const MATCH = { type: 'Match' };
+export const MISMATCH = { type: 'Mismatch' };
+export const DISALLOW_EMPTY = { type: 'DisallowEmpty' };
+
+const LEFTPARENTHESIS = 40;  // (
+const RIGHTPARENTHESIS = 41; // )
+
+function createCondition(match, thenBranch, elseBranch) {
+    // reduce node count
+    if (thenBranch === MATCH && elseBranch === MISMATCH) {
+        return match;
+    }
+
+    if (match === MATCH && thenBranch === MATCH && elseBranch === MATCH) {
+        return match;
+    }
+
+    if (match.type === 'If' && match.else === MISMATCH && thenBranch === MATCH) {
+        thenBranch = match.then;
+        match = match.match;
+    }
+
+    return {
+        type: 'If',
+        match,
+        then: thenBranch,
+        else: elseBranch
+    };
+}
+
+function isFunctionType(name) {
+    return (
+        name.length > 2 &&
+        name.charCodeAt(name.length - 2) === LEFTPARENTHESIS &&
+        name.charCodeAt(name.length - 1) === RIGHTPARENTHESIS
+    );
+}
+
+function isEnumCapatible(term) {
+    return (
+        term.type === 'Keyword' ||
+        term.type === 'AtKeyword' ||
+        term.type === 'Function' ||
+        term.type === 'Type' && isFunctionType(term.name)
+    );
+}
+
+function buildGroupMatchGraph(combinator, terms, atLeastOneTermMatched) {
+    switch (combinator) {
+        case ' ': {
+            // Juxtaposing components means that all of them must occur, in the given order.
+            //
+            // a b c
+            // =
+            // match a
+            //   then match b
+            //     then match c
+            //       then MATCH
+            //       else MISMATCH
+            //     else MISMATCH
+            //   else MISMATCH
+            let result = MATCH;
+
+            for (let i = terms.length - 1; i >= 0; i--) {
+                const term = terms[i];
+
+                result = createCondition(
+                    term,
+                    result,
+                    MISMATCH
+                );
+            };
+
+            return result;
+        }
+
+        case '|': {
+            // A bar (|) separates two or more alternatives: exactly one of them must occur.
+            //
+            // a | b | c
+            // =
+            // match a
+            //   then MATCH
+            //   else match b
+            //     then MATCH
+            //     else match c
+            //       then MATCH
+            //       else MISMATCH
+
+            let result = MISMATCH;
+            let map = null;
+
+            for (let i = terms.length - 1; i >= 0; i--) {
+                let term = terms[i];
+
+                // reduce sequence of keywords into a Enum
+                if (isEnumCapatible(term)) {
+                    if (map === null && i > 0 && isEnumCapatible(terms[i - 1])) {
+                        map = Object.create(null);
+                        result = createCondition(
+                            {
+                                type: 'Enum',
+                                map
+                            },
+                            MATCH,
+                            result
+                        );
+                    }
+
+                    if (map !== null) {
+                        const key = (isFunctionType(term.name) ? term.name.slice(0, -1) : term.name).toLowerCase();
+                        if (key in map === false) {
+                            map[key] = term;
+                            continue;
+                        }
+                    }
+                }
+
+                map = null;
+
+                // create a new conditonal node
+                result = createCondition(
+                    term,
+                    MATCH,
+                    result
+                );
+            };
+
+            return result;
+        }
+
+        case '&&': {
+            // A double ampersand (&&) separates two or more components,
+            // all of which must occur, in any order.
+
+            // Use MatchOnce for groups with a large number of terms,
+            // since &&-groups produces at least N!-node trees
+            if (terms.length > 5) {
+                return {
+                    type: 'MatchOnce',
+                    terms,
+                    all: true
+                };
+            }
+
+            // Use a combination tree for groups with small number of terms
+            //
+            // a && b && c
+            // =
+            // match a
+            //   then [b && c]
+            //   else match b
+            //     then [a && c]
+            //     else match c
+            //       then [a && b]
+            //       else MISMATCH
+            //
+            // a && b
+            // =
+            // match a
+            //   then match b
+            //     then MATCH
+            //     else MISMATCH
+            //   else match b
+            //     then match a
+            //       then MATCH
+            //       else MISMATCH
+            //     else MISMATCH
+            let result = MISMATCH;
+
+            for (let i = terms.length - 1; i >= 0; i--) {
+                const term = terms[i];
+                let thenClause;
+
+                if (terms.length > 1) {
+                    thenClause = buildGroupMatchGraph(
+                        combinator,
+                        terms.filter(function(newGroupTerm) {
+                            return newGroupTerm !== term;
+                        }),
+                        false
+                    );
+                } else {
+                    thenClause = MATCH;
+                }
+
+                result = createCondition(
+                    term,
+                    thenClause,
+                    result
+                );
+            };
+
+            return result;
+        }
+
+        case '||': {
+            // A double bar (||) separates two or more options:
+            // one or more of them must occur, in any order.
+
+            // Use MatchOnce for groups with a large number of terms,
+            // since ||-groups produces at least N!-node trees
+            if (terms.length > 5) {
+                return {
+                    type: 'MatchOnce',
+                    terms,
+                    all: false
+                };
+            }
+
+            // Use a combination tree for groups with small number of terms
+            //
+            // a || b || c
+            // =
+            // match a
+            //   then [b || c]
+            //   else match b
+            //     then [a || c]
+            //     else match c
+            //       then [a || b]
+            //       else MISMATCH
+            //
+            // a || b
+            // =
+            // match a
+            //   then match b
+            //     then MATCH
+            //     else MATCH
+            //   else match b
+            //     then match a
+            //       then MATCH
+            //       else MATCH
+            //     else MISMATCH
+            let result = atLeastOneTermMatched ? MATCH : MISMATCH;
+
+            for (let i = terms.length - 1; i >= 0; i--) {
+                const term = terms[i];
+                let thenClause;
+
+                if (terms.length > 1) {
+                    thenClause = buildGroupMatchGraph(
+                        combinator,
+                        terms.filter(function(newGroupTerm) {
+                            return newGroupTerm !== term;
+                        }),
+                        true
+                    );
+                } else {
+                    thenClause = MATCH;
+                }
+
+                result = createCondition(
+                    term,
+                    thenClause,
+                    result
+                );
+            };
+
+            return result;
+        }
+    }
+}
+
+function buildMultiplierMatchGraph(node) {
+    let result = MATCH;
+    let matchTerm = buildMatchGraphInternal(node.term);
+
+    if (node.max === 0) {
+        // disable repeating of empty match to prevent infinite loop
+        matchTerm = createCondition(
+            matchTerm,
+            DISALLOW_EMPTY,
+            MISMATCH
+        );
+
+        // an occurrence count is not limited, make a cycle;
+        // to collect more terms on each following matching mismatch
+        result = createCondition(
+            matchTerm,
+            null, // will be a loop
+            MISMATCH
+        );
+
+        result.then = createCondition(
+            MATCH,
+            MATCH,
+            result // make a loop
+        );
+
+        if (node.comma) {
+            result.then.else = createCondition(
+                { type: 'Comma', syntax: node },
+                result,
+                MISMATCH
+            );
+        }
+    } else {
+        // create a match node chain for [min .. max] interval with optional matches
+        for (let i = node.min || 1; i <= node.max; i++) {
+            if (node.comma && result !== MATCH) {
+                result = createCondition(
+                    { type: 'Comma', syntax: node },
+                    result,
+                    MISMATCH
+                );
+            }
+
+            result = createCondition(
+                matchTerm,
+                createCondition(
+                    MATCH,
+                    MATCH,
+                    result
+                ),
+                MISMATCH
+            );
+        }
+    }
+
+    if (node.min === 0) {
+        // allow zero match
+        result = createCondition(
+            MATCH,
+            MATCH,
+            result
+        );
+    } else {
+        // create a match node chain to collect [0 ... min - 1] required matches
+        for (let i = 0; i < node.min - 1; i++) {
+            if (node.comma && result !== MATCH) {
+                result = createCondition(
+                    { type: 'Comma', syntax: node },
+                    result,
+                    MISMATCH
+                );
+            }
+
+            result = createCondition(
+                matchTerm,
+                result,
+                MISMATCH
+            );
+        }
+    }
+
+    return result;
+}
+
+function buildMatchGraphInternal(node) {
+    if (typeof node === 'function') {
+        return {
+            type: 'Generic',
+            fn: node
+        };
+    }
+
+    switch (node.type) {
+        case 'Group': {
+            let result = buildGroupMatchGraph(
+                node.combinator,
+                node.terms.map(buildMatchGraphInternal),
+                false
+            );
+
+            if (node.disallowEmpty) {
+                result = createCondition(
+                    result,
+                    DISALLOW_EMPTY,
+                    MISMATCH
+                );
+            }
+
+            return result;
+        }
+
+        case 'Multiplier':
+            return buildMultiplierMatchGraph(node);
+
+        case 'Type':
+        case 'Property':
+            return {
+                type: node.type,
+                name: node.name,
+                syntax: node
+            };
+
+        case 'Keyword':
+            return {
+                type: node.type,
+                name: node.name.toLowerCase(),
+                syntax: node
+            };
+
+        case 'AtKeyword':
+            return {
+                type: node.type,
+                name: '@' + node.name.toLowerCase(),
+                syntax: node
+            };
+
+        case 'Function':
+            return {
+                type: node.type,
+                name: node.name.toLowerCase() + '(',
+                syntax: node
+            };
+
+        case 'String':
+            // convert a one char length String to a Token
+            if (node.value.length === 3) {
+                return {
+                    type: 'Token',
+                    value: node.value.charAt(1),
+                    syntax: node
+                };
+            }
+
+            // otherwise use it as is
+            return {
+                type: node.type,
+                value: node.value.substr(1, node.value.length - 2).replace(/\\'/g, '\''),
+                syntax: node
+            };
+
+        case 'Token':
+            return {
+                type: node.type,
+                value: node.value,
+                syntax: node
+            };
+
+        case 'Comma':
+            return {
+                type: node.type,
+                syntax: node
+            };
+
+        default:
+            throw new Error('Unknown node type:', node.type);
+    }
+}
+
+export function buildMatchGraph(syntaxTree, ref) {
+    if (typeof syntaxTree === 'string') {
+        syntaxTree = parse(syntaxTree);
+    }
+
+    return {
+        type: 'MatchGraph',
+        match: buildMatchGraphInternal(syntaxTree),
+        syntax: ref || null,
+        source: syntaxTree
+    };
+}

node_modules/css-tree/lib/lexer/match.js

@@ -0,0 +1,630 @@
+import { MATCH, MISMATCH, DISALLOW_EMPTY } from './match-graph.js';
+import * as TYPE from '../tokenizer/types.js';
+
+const { hasOwnProperty } = Object.prototype;
+const STUB = 0;
+const TOKEN = 1;
+const OPEN_SYNTAX = 2;
+const CLOSE_SYNTAX = 3;
+
+const EXIT_REASON_MATCH = 'Match';
+const EXIT_REASON_MISMATCH = 'Mismatch';
+const EXIT_REASON_ITERATION_LIMIT = 'Maximum iteration number exceeded (please fill an issue on https://github.com/csstree/csstree/issues)';
+
+const ITERATION_LIMIT = 15000;
+export let totalIterationCount = 0;
+
+function reverseList(list) {
+    let prev = null;
+    let next = null;
+    let item = list;
+
+    while (item !== null) {
+        next = item.prev;
+        item.prev = prev;
+        prev = item;
+        item = next;
+    }
+
+    return prev;
+}
+
+function areStringsEqualCaseInsensitive(testStr, referenceStr) {
+    if (testStr.length !== referenceStr.length) {
+        return false;
+    }
+
+    for (let i = 0; i < testStr.length; i++) {
+        const referenceCode = referenceStr.charCodeAt(i);
+        let testCode = testStr.charCodeAt(i);
+
+        // testCode.toLowerCase() for U+0041 LATIN CAPITAL LETTER A (A) .. U+005A LATIN CAPITAL LETTER Z (Z).
+        if (testCode >= 0x0041 && testCode <= 0x005A) {
+            testCode = testCode | 32;
+        }
+
+        if (testCode !== referenceCode) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+function isContextEdgeDelim(token) {
+    if (token.type !== TYPE.Delim) {
+        return false;
+    }
+
+    // Fix matching for unicode-range: U+30??, U+FF00-FF9F
+    // Probably we need to check out previous match instead
+    return token.value !== '?';
+}
+
+function isCommaContextStart(token) {
+    if (token === null) {
+        return true;
+    }
+
+    return (
+        token.type === TYPE.Comma ||
+        token.type === TYPE.Function ||
+        token.type === TYPE.LeftParenthesis ||
+        token.type === TYPE.LeftSquareBracket ||
+        token.type === TYPE.LeftCurlyBracket ||
+        isContextEdgeDelim(token)
+    );
+}
+
+function isCommaContextEnd(token) {
+    if (token === null) {
+        return true;
+    }
+
+    return (
+        token.type === TYPE.RightParenthesis ||
+        token.type === TYPE.RightSquareBracket ||
+        token.type === TYPE.RightCurlyBracket ||
+        (token.type === TYPE.Delim && token.value === '/')
+    );
+}
+
+function internalMatch(tokens, state, syntaxes) {
+    function moveToNextToken() {
+        do {
+            tokenIndex++;
+            token = tokenIndex < tokens.length ? tokens[tokenIndex] : null;
+        } while (token !== null && (token.type === TYPE.WhiteSpace || token.type === TYPE.Comment));
+    }
+
+    function getNextToken(offset) {
+        const nextIndex = tokenIndex + offset;
+
+        return nextIndex < tokens.length ? tokens[nextIndex] : null;
+    }
+
+    function stateSnapshotFromSyntax(nextState, prev) {
+        return {
+            nextState,
+            matchStack,
+            syntaxStack,
+            thenStack,
+            tokenIndex,
+            prev
+        };
+    }
+
+    function pushThenStack(nextState) {
+        thenStack = {
+            nextState,
+            matchStack,
+            syntaxStack,
+            prev: thenStack
+        };
+    }
+
+    function pushElseStack(nextState) {
+        elseStack = stateSnapshotFromSyntax(nextState, elseStack);
+    }
+
+    function addTokenToMatch() {
+        matchStack = {
+            type: TOKEN,
+            syntax: state.syntax,
+            token,
+            prev: matchStack
+        };
+
+        moveToNextToken();
+        syntaxStash = null;
+
+        if (tokenIndex > longestMatch) {
+            longestMatch = tokenIndex;
+        }
+    }
+
+    function openSyntax() {
+        syntaxStack = {
+            syntax: state.syntax,
+            opts: state.syntax.opts || (syntaxStack !== null && syntaxStack.opts) || null,
+            prev: syntaxStack
+        };
+
+        matchStack = {
+            type: OPEN_SYNTAX,
+            syntax: state.syntax,
+            token: matchStack.token,
+            prev: matchStack
+        };
+    }
+
+    function closeSyntax() {
+        if (matchStack.type === OPEN_SYNTAX) {
+            matchStack = matchStack.prev;
+        } else {
+            matchStack = {
+                type: CLOSE_SYNTAX,
+                syntax: syntaxStack.syntax,
+                token: matchStack.token,
+                prev: matchStack
+            };
+        }
+
+        syntaxStack = syntaxStack.prev;
+    }
+
+    let syntaxStack = null;
+    let thenStack = null;
+    let elseStack = null;
+
+    // null – stashing allowed, nothing stashed
+    // false – stashing disabled, nothing stashed
+    // anithing else – fail stashable syntaxes, some syntax stashed
+    let syntaxStash = null;
+
+    let iterationCount = 0; // count iterations and prevent infinite loop
+    let exitReason = null;
+
+    let token = null;
+    let tokenIndex = -1;
+    let longestMatch = 0;
+    let matchStack = {
+        type: STUB,
+        syntax: null,
+        token: null,
+        prev: null
+    };
+
+    moveToNextToken();
+
+    while (exitReason === null && ++iterationCount < ITERATION_LIMIT) {
+        // function mapList(list, fn) {
+        //     const result = [];
+        //     while (list) {
+        //         result.unshift(fn(list));
+        //         list = list.prev;
+        //     }
+        //     return result;
+        // }
+        // console.log('--\n',
+        //     '#' + iterationCount,
+        //     require('util').inspect({
+        //         match: mapList(matchStack, x => x.type === TOKEN ? x.token && x.token.value : x.syntax ? ({ [OPEN_SYNTAX]: '<', [CLOSE_SYNTAX]: '</' }[x.type] || x.type) + '!' + x.syntax.name : null),
+        //         token: token && token.value,
+        //         tokenIndex,
+        //         syntax: syntax.type + (syntax.id ? ' #' + syntax.id : '')
+        //     }, { depth: null })
+        // );
+        switch (state.type) {
+            case 'Match':
+                if (thenStack === null) {
+                    // turn to MISMATCH when some tokens left unmatched
+                    if (token !== null) {
+                        // doesn't mismatch if just one token left and it's an IE hack
+                        if (tokenIndex !== tokens.length - 1 || (token.value !== '\\0' && token.value !== '\\9')) {
+                            state = MISMATCH;
+                            break;
+                        }
+                    }
+
+                    // break the main loop, return a result - MATCH
+                    exitReason = EXIT_REASON_MATCH;
+                    break;
+                }
+
+                // go to next syntax (`then` branch)
+                state = thenStack.nextState;
+
+                // check match is not empty
+                if (state === DISALLOW_EMPTY) {
+                    if (thenStack.matchStack === matchStack) {
+                        state = MISMATCH;
+                        break;
+                    } else {
+                        state = MATCH;
+                    }
+                }
+
+                // close syntax if needed
+                while (thenStack.syntaxStack !== syntaxStack) {
+                    closeSyntax();
+                }
+
+                // pop stack
+                thenStack = thenStack.prev;
+                break;
+
+            case 'Mismatch':
+                // when some syntax is stashed
+                if (syntaxStash !== null && syntaxStash !== false) {
+                    // there is no else branches or a branch reduce match stack
+                    if (elseStack === null || tokenIndex > elseStack.tokenIndex) {
+                        // restore state from the stash
+                        elseStack = syntaxStash;
+                        syntaxStash = false; // disable stashing
+                    }
+                } else if (elseStack === null) {
+                    // no else branches -> break the main loop
+                    // return a result - MISMATCH
+                    exitReason = EXIT_REASON_MISMATCH;
+                    break;
+                }
+
+                // go to next syntax (`else` branch)
+                state = elseStack.nextState;
+
+                // restore all the rest stack states
+                thenStack = elseStack.thenStack;
+                syntaxStack = elseStack.syntaxStack;
+                matchStack = elseStack.matchStack;
+                tokenIndex = elseStack.tokenIndex;
+                token = tokenIndex < tokens.length ? tokens[tokenIndex] : null;
+
+                // pop stack
+                elseStack = elseStack.prev;
+                break;
+
+            case 'MatchGraph':
+                state = state.match;
+                break;
+
+            case 'If':
+                // IMPORTANT: else stack push must go first,
+                // since it stores the state of thenStack before changes
+                if (state.else !== MISMATCH) {
+                    pushElseStack(state.else);
+                }
+
+                if (state.then !== MATCH) {
+                    pushThenStack(state.then);
+                }
+
+                state = state.match;
+                break;
+
+            case 'MatchOnce':
+                state = {
+                    type: 'MatchOnceBuffer',
+                    syntax: state,
+                    index: 0,
+                    mask: 0
+                };
+                break;
+
+            case 'MatchOnceBuffer': {
+                const terms = state.syntax.terms;
+
+                if (state.index === terms.length) {
+                    // no matches at all or it's required all terms to be matched
+                    if (state.mask === 0 || state.syntax.all) {
+                        state = MISMATCH;
+                        break;
+                    }
+
+                    // a partial match is ok
+                    state = MATCH;
+                    break;
+                }
+
+                // all terms are matched
+                if (state.mask === (1 << terms.length) - 1) {
+                    state = MATCH;
+                    break;
+                }
+
+                for (; state.index < terms.length; state.index++) {
+                    const matchFlag = 1 << state.index;
+
+                    if ((state.mask & matchFlag) === 0) {
+                        // IMPORTANT: else stack push must go first,
+                        // since it stores the state of thenStack before changes
+                        pushElseStack(state);
+                        pushThenStack({
+                            type: 'AddMatchOnce',
+                            syntax: state.syntax,
+                            mask: state.mask | matchFlag
+                        });
+
+                        // match
+                        state = terms[state.index++];
+                        break;
+                    }
+                }
+                break;
+            }
+
+            case 'AddMatchOnce':
+                state = {
+                    type: 'MatchOnceBuffer',
+                    syntax: state.syntax,
+                    index: 0,
+                    mask: state.mask
+                };
+                break;
+
+            case 'Enum':
+                if (token !== null) {
+                    let name = token.value.toLowerCase();
+
+                    // drop \0 and \9 hack from keyword name
+                    if (name.indexOf('\\') !== -1) {
+                        name = name.replace(/\\[09].*$/, '');
+                    }
+
+                    if (hasOwnProperty.call(state.map, name)) {
+                        state = state.map[name];
+                        break;
+                    }
+                }
+
+                state = MISMATCH;
+                break;
+
+            case 'Generic': {
+                const opts = syntaxStack !== null ? syntaxStack.opts : null;
+                const lastTokenIndex = tokenIndex + Math.floor(state.fn(token, getNextToken, opts));
+
+                if (!isNaN(lastTokenIndex) && lastTokenIndex > tokenIndex) {
+                    while (tokenIndex < lastTokenIndex) {
+                        addTokenToMatch();
+                    }
+
+                    state = MATCH;
+                } else {
+                    state = MISMATCH;
+                }
+
+                break;
+            }
+
+            case 'Type':
+            case 'Property': {
+                const syntaxDict = state.type === 'Type' ? 'types' : 'properties';
+                const dictSyntax = hasOwnProperty.call(syntaxes, syntaxDict) ? syntaxes[syntaxDict][state.name] : null;
+
+                if (!dictSyntax || !dictSyntax.match) {
+                    throw new Error(
+                        'Bad syntax reference: ' +
+                        (state.type === 'Type'
+                            ? '<' + state.name + '>'
+                            : '<\'' + state.name + '\'>')
+                    );
+                }
+
+                // stash a syntax for types with low priority
+                if (syntaxStash !== false && token !== null && state.type === 'Type') {
+                    const lowPriorityMatching =
+                        // https://drafts.csswg.org/css-values-4/#custom-idents
+                        // When parsing positionally-ambiguous keywords in a property value, a <custom-ident> production
+                        // can only claim the keyword if no other unfulfilled production can claim it.
+                        (state.name === 'custom-ident' && token.type === TYPE.Ident) ||
+
+                        // https://drafts.csswg.org/css-values-4/#lengths
+                        // ... if a `0` could be parsed as either a <number> or a <length> in a property (such as line-height),
+                        // it must parse as a <number>
+                        (state.name === 'length' && token.value === '0');
+
+                    if (lowPriorityMatching) {
+                        if (syntaxStash === null) {
+                            syntaxStash = stateSnapshotFromSyntax(state, elseStack);
+                        }
+
+                        state = MISMATCH;
+                        break;
+                    }
+                }
+
+                openSyntax();
+                state = dictSyntax.match;
+                break;
+            }
+
+            case 'Keyword': {
+                const name = state.name;
+
+                if (token !== null) {
+                    let keywordName = token.value;
+
+                    // drop \0 and \9 hack from keyword name
+                    if (keywordName.indexOf('\\') !== -1) {
+                        keywordName = keywordName.replace(/\\[09].*$/, '');
+                    }
+
+                    if (areStringsEqualCaseInsensitive(keywordName, name)) {
+                        addTokenToMatch();
+                        state = MATCH;
+                        break;
+                    }
+                }
+
+                state = MISMATCH;
+                break;
+            }
+
+            case 'AtKeyword':
+            case 'Function':
+                if (token !== null && areStringsEqualCaseInsensitive(token.value, state.name)) {
+                    addTokenToMatch();
+                    state = MATCH;
+                    break;
+                }
+
+                state = MISMATCH;
+                break;
+
+            case 'Token':
+                if (token !== null && token.value === state.value) {
+                    addTokenToMatch();
+                    state = MATCH;
+                    break;
+                }
+
+                state = MISMATCH;
+                break;
+
+            case 'Comma':
+                if (token !== null && token.type === TYPE.Comma) {
+                    if (isCommaContextStart(matchStack.token)) {
+                        state = MISMATCH;
+                    } else {
+                        addTokenToMatch();
+                        state = isCommaContextEnd(token) ? MISMATCH : MATCH;
+                    }
+                } else {
+                    state = isCommaContextStart(matchStack.token) || isCommaContextEnd(token) ? MATCH : MISMATCH;
+                }
+
+                break;
+
+            case 'String':
+                let string = '';
+                let lastTokenIndex = tokenIndex;
+
+                for (; lastTokenIndex < tokens.length && string.length < state.value.length; lastTokenIndex++) {
+                    string += tokens[lastTokenIndex].value;
+                }
+
+                if (areStringsEqualCaseInsensitive(string, state.value)) {
+                    while (tokenIndex < lastTokenIndex) {
+                        addTokenToMatch();
+                    }
+
+                    state = MATCH;
+                } else {
+                    state = MISMATCH;
+                }
+
+                break;
+
+            default:
+                throw new Error('Unknown node type: ' + state.type);
+        }
+    }
+
+    totalIterationCount += iterationCount;
+
+    switch (exitReason) {
+        case null:
+            console.warn('[csstree-match] BREAK after ' + ITERATION_LIMIT + ' iterations');
+            exitReason = EXIT_REASON_ITERATION_LIMIT;
+            matchStack = null;
+            break;
+
+        case EXIT_REASON_MATCH:
+            while (syntaxStack !== null) {
+                closeSyntax();
+            }
+            break;
+
+        default:
+            matchStack = null;
+    }
+
+    return {
+        tokens,
+        reason: exitReason,
+        iterations: iterationCount,
+        match: matchStack,
+        longestMatch
+    };
+}
+
+export function matchAsList(tokens, matchGraph, syntaxes) {
+    const matchResult = internalMatch(tokens, matchGraph, syntaxes || {});
+
+    if (matchResult.match !== null) {
+        let item = reverseList(matchResult.match).prev;
+
+        matchResult.match = [];
+
+        while (item !== null) {
+            switch (item.type) {
+                case OPEN_SYNTAX:
+                case CLOSE_SYNTAX:
+                    matchResult.match.push({
+                        type: item.type,
+                        syntax: item.syntax
+                    });
+                    break;
+
+                default:
+                    matchResult.match.push({
+                        token: item.token.value,
+                        node: item.token.node
+                    });
+                    break;
+            }
+
+            item = item.prev;
+        }
+    }
+
+    return matchResult;
+}
+
+export function matchAsTree(tokens, matchGraph, syntaxes) {
+    const matchResult = internalMatch(tokens, matchGraph, syntaxes || {});
+
+    if (matchResult.match === null) {
+        return matchResult;
+    }
+
+    let item = matchResult.match;
+    let host = matchResult.match = {
+        syntax: matchGraph.syntax || null,
+        match: []
+    };
+    const hostStack = [host];
+
+    // revert a list and start with 2nd item since 1st is a stub item
+    item = reverseList(item).prev;
+
+    // build a tree
+    while (item !== null) {
+        switch (item.type) {
+            case OPEN_SYNTAX:
+                host.match.push(host = {
+                    syntax: item.syntax,
+                    match: []
+                });
+                hostStack.push(host);
+                break;
+
+            case CLOSE_SYNTAX:
+                hostStack.pop();
+                host = hostStack[hostStack.length - 1];
+                break;
+
+            default:
+                host.match.push({
+                    syntax: item.syntax || null,
+                    token: item.token.value,
+                    node: item.token.node
+                });
+        }
+
+        item = item.prev;
+    }
+
+    return matchResult;
+}

node_modules/css-tree/lib/lexer/prepare-tokens.js

@@ -0,0 +1,50 @@
+import { tokenize } from '../tokenizer/index.js';
+
+const astToTokens = {
+    decorator(handlers) {
+        const tokens = [];
+        let curNode = null;
+
+        return {
+            ...handlers,
+            node(node) {
+                const tmp = curNode;
+                curNode = node;
+                handlers.node.call(this, node);
+                curNode = tmp;
+            },
+            emit(value, type, auto) {
+                tokens.push({
+                    type,
+                    value,
+                    node: auto ? null : curNode
+                });
+            },
+            result() {
+                return tokens;
+            }
+        };
+    }
+};
+
+function stringToTokens(str) {
+    const tokens = [];
+
+    tokenize(str, (type, start, end) =>
+        tokens.push({
+            type,
+            value: str.slice(start, end),
+            node: null
+        })
+    );
+
+    return tokens;
+}
+
+export default function(value, syntax) {
+    if (typeof value === 'string') {
+        return stringToTokens(value);
+    }
+
+    return syntax.generate(value, astToTokens);
+};

node_modules/css-tree/lib/lexer/search.js

@@ -0,0 +1,61 @@
+import { List } from '../utils/List.js';
+
+function getFirstMatchNode(matchNode) {
+    if ('node' in matchNode) {
+        return matchNode.node;
+    }
+
+    return getFirstMatchNode(matchNode.match[0]);
+}
+
+function getLastMatchNode(matchNode) {
+    if ('node' in matchNode) {
+        return matchNode.node;
+    }
+
+    return getLastMatchNode(matchNode.match[matchNode.match.length - 1]);
+}
+
+export function matchFragments(lexer, ast, match, type, name) {
+    function findFragments(matchNode) {
+        if (matchNode.syntax !== null &&
+            matchNode.syntax.type === type &&
+            matchNode.syntax.name === name) {
+            const start = getFirstMatchNode(matchNode);
+            const end = getLastMatchNode(matchNode);
+
+            lexer.syntax.walk(ast, function(node, item, list) {
+                if (node === start) {
+                    const nodes = new List();
+
+                    do {
+                        nodes.appendData(item.data);
+
+                        if (item.data === end) {
+                            break;
+                        }
+
+                        item = item.next;
+                    } while (item !== null);
+
+                    fragments.push({
+                        parent: list,
+                        nodes
+                    });
+                }
+            });
+        }
+
+        if (Array.isArray(matchNode.match)) {
+            matchNode.match.forEach(findFragments);
+        }
+    }
+
+    const fragments = [];
+
+    if (match.matched !== null) {
+        findFragments(match.matched);
+    }
+
+    return fragments;
+}

node_modules/css-tree/lib/lexer/structure.js

@@ -0,0 +1,164 @@
+import { List } from '../utils/List.js';
+
+const { hasOwnProperty } = Object.prototype;
+
+function isValidNumber(value) {
+    // Number.isInteger(value) && value >= 0
+    return (
+        typeof value === 'number' &&
+        isFinite(value) &&
+        Math.floor(value) === value &&
+        value >= 0
+    );
+}
+
+function isValidLocation(loc) {
+    return (
+        Boolean(loc) &&
+        isValidNumber(loc.offset) &&
+        isValidNumber(loc.line) &&
+        isValidNumber(loc.column)
+    );
+}
+
+function createNodeStructureChecker(type, fields) {
+    return function checkNode(node, warn) {
+        if (!node || node.constructor !== Object) {
+            return warn(node, 'Type of node should be an Object');
+        }
+
+        for (let key in node) {
+            let valid = true;
+
+            if (hasOwnProperty.call(node, key) === false) {
+                continue;
+            }
+
+            if (key === 'type') {
+                if (node.type !== type) {
+                    warn(node, 'Wrong node type `' + node.type + '`, expected `' + type + '`');
+                }
+            } else if (key === 'loc') {
+                if (node.loc === null) {
+                    continue;
+                } else if (node.loc && node.loc.constructor === Object) {
+                    if (typeof node.loc.source !== 'string') {
+                        key += '.source';
+                    } else if (!isValidLocation(node.loc.start)) {
+                        key += '.start';
+                    } else if (!isValidLocation(node.loc.end)) {
+                        key += '.end';
+                    } else {
+                        continue;
+                    }
+                }
+
+                valid = false;
+            } else if (fields.hasOwnProperty(key)) {
+                valid = false;
+
+                for (let i = 0; !valid && i < fields[key].length; i++) {
+                    const fieldType = fields[key][i];
+
+                    switch (fieldType) {
+                        case String:
+                            valid = typeof node[key] === 'string';
+                            break;
+
+                        case Boolean:
+                            valid = typeof node[key] === 'boolean';
+                            break;
+
+                        case null:
+                            valid = node[key] === null;
+                            break;
+
+                        default:
+                            if (typeof fieldType === 'string') {
+                                valid = node[key] && node[key].type === fieldType;
+                            } else if (Array.isArray(fieldType)) {
+                                valid = node[key] instanceof List;
+                            }
+                    }
+                }
+            } else {
+                warn(node, 'Unknown field `' + key + '` for ' + type + ' node type');
+            }
+
+            if (!valid) {
+                warn(node, 'Bad value for `' + type + '.' + key + '`');
+            }
+        }
+
+        for (const key in fields) {
+            if (hasOwnProperty.call(fields, key) &&
+                hasOwnProperty.call(node, key) === false) {
+                warn(node, 'Field `' + type + '.' + key + '` is missed');
+            }
+        }
+    };
+}
+
+function processStructure(name, nodeType) {
+    const structure = nodeType.structure;
+    const fields = {
+        type: String,
+        loc: true
+    };
+    const docs = {
+        type: '"' + name + '"'
+    };
+
+    for (const key in structure) {
+        if (hasOwnProperty.call(structure, key) === false) {
+            continue;
+        }
+
+        const docsTypes = [];
+        const fieldTypes = fields[key] = Array.isArray(structure[key])
+            ? structure[key].slice()
+            : [structure[key]];
+
+        for (let i = 0; i < fieldTypes.length; i++) {
+            const fieldType = fieldTypes[i];
+            if (fieldType === String || fieldType === Boolean) {
+                docsTypes.push(fieldType.name);
+            } else if (fieldType === null) {
+                docsTypes.push('null');
+            } else if (typeof fieldType === 'string') {
+                docsTypes.push('<' + fieldType + '>');
+            } else if (Array.isArray(fieldType)) {
+                docsTypes.push('List'); // TODO: use type enum
+            } else {
+                throw new Error('Wrong value `' + fieldType + '` in `' + name + '.' + key + '` structure definition');
+            }
+        }
+
+        docs[key] = docsTypes.join(' | ');
+    }
+
+    return {
+        docs,
+        check: createNodeStructureChecker(name, fields)
+    };
+}
+
+export function getStructureFromConfig(config) {
+    const structure = {};
+
+    if (config.node) {
+        for (const name in config.node) {
+            if (hasOwnProperty.call(config.node, name)) {
+                const nodeType = config.node[name];
+
+                if (nodeType.structure) {
+                    structure[name] = processStructure(name, nodeType);
+                } else {
+                    throw new Error('Missed `structure` field in `' + name + '` node type definition');
+                }
+            }
+        }
+    }
+
+    return structure;
+};

node_modules/css-tree/lib/lexer/trace.js

@@ -0,0 +1,66 @@
+export function getTrace(node) {
+    function shouldPutToTrace(syntax) {
+        if (syntax === null) {
+            return false;
+        }
+
+        return (
+            syntax.type === 'Type' ||
+            syntax.type === 'Property' ||
+            syntax.type === 'Keyword'
+        );
+    }
+
+    function hasMatch(matchNode) {
+        if (Array.isArray(matchNode.match)) {
+            // use for-loop for better perfomance
+            for (let i = 0; i < matchNode.match.length; i++) {
+                if (hasMatch(matchNode.match[i])) {
+                    if (shouldPutToTrace(matchNode.syntax)) {
+                        result.unshift(matchNode.syntax);
+                    }
+
+                    return true;
+                }
+            }
+        } else if (matchNode.node === node) {
+            result = shouldPutToTrace(matchNode.syntax)
+                ? [matchNode.syntax]
+                : [];
+
+            return true;
+        }
+
+        return false;
+    }
+
+    let result = null;
+
+    if (this.matched !== null) {
+        hasMatch(this.matched);
+    }
+
+    return result;
+}
+
+export function isType(node, type) {
+    return testNode(this, node, match => match.type === 'Type' && match.name === type);
+}
+
+export function isProperty(node, property) {
+    return testNode(this, node, match => match.type === 'Property' && match.name === property);
+}
+
+export function isKeyword(node) {
+    return testNode(this, node, match => match.type === 'Keyword');
+}
+
+function testNode(match, node, fn) {
+    const trace = getTrace.call(match, node);
+
+    if (trace === null) {
+        return false;
+    }
+
+    return trace.some(fn);
+}

node_modules/css-tree/lib/parser/SyntaxError.js

@@ -0,0 +1,65 @@
+import { createCustomError } from '../utils/create-custom-error.js';
+
+const MAX_LINE_LENGTH = 100;
+const OFFSET_CORRECTION = 60;
+const TAB_REPLACEMENT = '    ';
+
+function sourceFragment({ source, line, column }, extraLines) {
+    function processLines(start, end) {
+        return lines
+            .slice(start, end)
+            .map((line, idx) =>
+                String(start + idx + 1).padStart(maxNumLength) + ' |' + line
+            ).join('\n');
+    }
+
+    const lines = source.split(/\r\n?|\n|\f/);
+    const startLine = Math.max(1, line - extraLines) - 1;
+    const endLine = Math.min(line + extraLines, lines.length + 1);
+    const maxNumLength = Math.max(4, String(endLine).length) + 1;
+    let cutLeft = 0;
+
+    // column correction according to replaced tab before column
+    column += (TAB_REPLACEMENT.length - 1) * (lines[line - 1].substr(0, column - 1).match(/\t/g) || []).length;
+
+    if (column > MAX_LINE_LENGTH) {
+        cutLeft = column - OFFSET_CORRECTION + 3;
+        column = OFFSET_CORRECTION - 2;
+    }
+
+    for (let i = startLine; i <= endLine; i++) {
+        if (i >= 0 && i < lines.length) {
+            lines[i] = lines[i].replace(/\t/g, TAB_REPLACEMENT);
+            lines[i] =
+                (cutLeft > 0 && lines[i].length > cutLeft ? '\u2026' : '') +
+                lines[i].substr(cutLeft, MAX_LINE_LENGTH - 2) +
+                (lines[i].length > cutLeft + MAX_LINE_LENGTH - 1 ? '\u2026' : '');
+        }
+    }
+
+    return [
+        processLines(startLine, line),
+        new Array(column + maxNumLength + 2).join('-') + '^',
+        processLines(line, endLine)
+    ].filter(Boolean).join('\n');
+}
+
+export function SyntaxError(message, source, offset, line, column) {
+    const error = Object.assign(createCustomError('SyntaxError', message), {
+        source,
+        offset,
+        line,
+        column,
+        sourceFragment(extraLines) {
+            return sourceFragment({ source, line, column }, isNaN(extraLines) ? 0 : extraLines);
+        },
+        get formattedMessage() {
+            return (
+                `Parse error: ${message}\n` +
+                sourceFragment({ source, line, column }, 2)
+            );
+        }
+    });
+
+    return error;
+}

node_modules/css-tree/lib/parser/create.js

@@ -0,0 +1,346 @@
+import { List } from '../utils/List.js';
+import { SyntaxError } from './SyntaxError.js';
+import {
+    tokenize,
+    OffsetToLocation,
+    TokenStream,
+    tokenNames,
+
+    consumeNumber,
+    findWhiteSpaceStart,
+    cmpChar,
+    cmpStr,
+
+    WhiteSpace,
+    Comment,
+    Ident,
+    Function as FunctionToken,
+    Url,
+    Hash,
+    Percentage,
+    Number as NumberToken
+} from '../tokenizer/index.js';
+import { readSequence } from './sequence.js';
+
+const NOOP = () => {};
+const EXCLAMATIONMARK = 0x0021;  // U+0021 EXCLAMATION MARK (!)
+const NUMBERSIGN = 0x0023;       // U+0023 NUMBER SIGN (#)
+const SEMICOLON = 0x003B;        // U+003B SEMICOLON (;)
+const LEFTCURLYBRACKET = 0x007B; // U+007B LEFT CURLY BRACKET ({)
+const NULL = 0;
+
+function createParseContext(name) {
+    return function() {
+        return this[name]();
+    };
+}
+
+function fetchParseValues(dict) {
+    const result = Object.create(null);
+
+    for (const name in dict) {
+        const item = dict[name];
+        const fn = item.parse || item;
+
+        if (fn) {
+            result[name] = fn;
+        }
+    }
+
+    return result;
+}
+
+function processConfig(config) {
+    const parseConfig = {
+        context: Object.create(null),
+        scope: Object.assign(Object.create(null), config.scope),
+        atrule: fetchParseValues(config.atrule),
+        pseudo: fetchParseValues(config.pseudo),
+        node: fetchParseValues(config.node)
+    };
+
+    for (const name in config.parseContext) {
+        switch (typeof config.parseContext[name]) {
+            case 'function':
+                parseConfig.context[name] = config.parseContext[name];
+                break;
+
+            case 'string':
+                parseConfig.context[name] = createParseContext(config.parseContext[name]);
+                break;
+        }
+    }
+
+    return {
+        config: parseConfig,
+        ...parseConfig,
+        ...parseConfig.node
+    };
+}
+
+export function createParser(config) {
+    let source = '';
+    let filename = '<unknown>';
+    let needPositions = false;
+    let onParseError = NOOP;
+    let onParseErrorThrow = false;
+
+    const locationMap = new OffsetToLocation();
+    const parser = Object.assign(new TokenStream(), processConfig(config || {}), {
+        parseAtrulePrelude: true,
+        parseRulePrelude: true,
+        parseValue: true,
+        parseCustomProperty: false,
+
+        readSequence,
+
+        consumeUntilBalanceEnd: () => 0,
+        consumeUntilLeftCurlyBracket(code) {
+            return code === LEFTCURLYBRACKET ? 1 : 0;
+        },
+        consumeUntilLeftCurlyBracketOrSemicolon(code) {
+            return code === LEFTCURLYBRACKET || code === SEMICOLON ? 1 : 0;
+        },
+        consumeUntilExclamationMarkOrSemicolon(code) {
+            return code === EXCLAMATIONMARK || code === SEMICOLON ? 1 : 0;
+        },
+        consumeUntilSemicolonIncluded(code) {
+            return code === SEMICOLON ? 2 : 0;
+        },
+
+        createList() {
+            return new List();
+        },
+        createSingleNodeList(node) {
+            return new List().appendData(node);
+        },
+        getFirstListNode(list) {
+            return list && list.first;
+        },
+        getLastListNode(list) {
+            return list && list.last;
+        },
+
+        parseWithFallback(consumer, fallback) {
+            const startToken = this.tokenIndex;
+
+            try {
+                return consumer.call(this);
+            } catch (e) {
+                if (onParseErrorThrow) {
+                    throw e;
+                }
+
+                const fallbackNode = fallback.call(this, startToken);
+
+                onParseErrorThrow = true;
+                onParseError(e, fallbackNode);
+                onParseErrorThrow = false;
+
+                return fallbackNode;
+            }
+        },
+
+        lookupNonWSType(offset) {
+            let type;
+
+            do {
+                type = this.lookupType(offset++);
+                if (type !== WhiteSpace) {
+                    return type;
+                }
+            } while (type !== NULL);
+
+            return NULL;
+        },
+
+        charCodeAt(offset) {
+            return offset >= 0 && offset < source.length ? source.charCodeAt(offset) : 0;
+        },
+        substring(offsetStart, offsetEnd) {
+            return source.substring(offsetStart, offsetEnd);
+        },
+        substrToCursor(start) {
+            return this.source.substring(start, this.tokenStart);
+        },
+
+        cmpChar(offset, charCode) {
+            return cmpChar(source, offset, charCode);
+        },
+        cmpStr(offsetStart, offsetEnd, str) {
+            return cmpStr(source, offsetStart, offsetEnd, str);
+        },
+
+        consume(tokenType) {
+            const start = this.tokenStart;
+
+            this.eat(tokenType);
+
+            return this.substrToCursor(start);
+        },
+        consumeFunctionName() {
+            const name = source.substring(this.tokenStart, this.tokenEnd - 1);
+
+            this.eat(FunctionToken);
+
+            return name;
+        },
+        consumeNumber(type) {
+            const number = source.substring(this.tokenStart, consumeNumber(source, this.tokenStart));
+
+            this.eat(type);
+
+            return number;
+        },
+
+        eat(tokenType) {
+            if (this.tokenType !== tokenType) {
+                const tokenName = tokenNames[tokenType].slice(0, -6).replace(/-/g, ' ').replace(/^./, m => m.toUpperCase());
+                let message = `${/[[\](){}]/.test(tokenName) ? `"${tokenName}"` : tokenName} is expected`;
+                let offset = this.tokenStart;
+
+                // tweak message and offset
+                switch (tokenType) {
+                    case Ident:
+                        // when identifier is expected but there is a function or url
+                        if (this.tokenType === FunctionToken || this.tokenType === Url) {
+                            offset = this.tokenEnd - 1;
+                            message = 'Identifier is expected but function found';
+                        } else {
+                            message = 'Identifier is expected';
+                        }
+                        break;
+
+                    case Hash:
+                        if (this.isDelim(NUMBERSIGN)) {
+                            this.next();
+                            offset++;
+                            message = 'Name is expected';
+                        }
+                        break;
+
+                    case Percentage:
+                        if (this.tokenType === NumberToken) {
+                            offset = this.tokenEnd;
+                            message = 'Percent sign is expected';
+                        }
+                        break;
+                }
+
+                this.error(message, offset);
+            }
+
+            this.next();
+        },
+        eatIdent(name) {
+            if (this.tokenType !== Ident || this.lookupValue(0, name) === false) {
+                this.error(`Identifier "${name}" is expected`);
+            }
+
+            this.next();
+        },
+        eatDelim(code) {
+            if (!this.isDelim(code)) {
+                this.error(`Delim "${String.fromCharCode(code)}" is expected`);
+            }
+
+            this.next();
+        },
+
+        getLocation(start, end) {
+            if (needPositions) {
+                return locationMap.getLocationRange(
+                    start,
+                    end,
+                    filename
+                );
+            }
+
+            return null;
+        },
+        getLocationFromList(list) {
+            if (needPositions) {
+                const head = this.getFirstListNode(list);
+                const tail = this.getLastListNode(list);
+                return locationMap.getLocationRange(
+                    head !== null ? head.loc.start.offset - locationMap.startOffset : this.tokenStart,
+                    tail !== null ? tail.loc.end.offset - locationMap.startOffset : this.tokenStart,
+                    filename
+                );
+            }
+
+            return null;
+        },
+
+        error(message, offset) {
+            const location = typeof offset !== 'undefined' && offset < source.length
+                ? locationMap.getLocation(offset)
+                : this.eof
+                    ? locationMap.getLocation(findWhiteSpaceStart(source, source.length - 1))
+                    : locationMap.getLocation(this.tokenStart);
+
+            throw new SyntaxError(
+                message || 'Unexpected input',
+                source,
+                location.offset,
+                location.line,
+                location.column
+            );
+        }
+    });
+
+    const parse = function(source_, options) {
+        source = source_;
+        options = options || {};
+
+        parser.setSource(source, tokenize);
+        locationMap.setSource(
+            source,
+            options.offset,
+            options.line,
+            options.column
+        );
+
+        filename = options.filename || '<unknown>';
+        needPositions = Boolean(options.positions);
+        onParseError = typeof options.onParseError === 'function' ? options.onParseError : NOOP;
+        onParseErrorThrow = false;
+
+        parser.parseAtrulePrelude = 'parseAtrulePrelude' in options ? Boolean(options.parseAtrulePrelude) : true;
+        parser.parseRulePrelude = 'parseRulePrelude' in options ? Boolean(options.parseRulePrelude) : true;
+        parser.parseValue = 'parseValue' in options ? Boolean(options.parseValue) : true;
+        parser.parseCustomProperty = 'parseCustomProperty' in options ? Boolean(options.parseCustomProperty) : false;
+
+        const { context = 'default', onComment } = options;
+
+        if (context in parser.context === false) {
+            throw new Error('Unknown context `' + context + '`');
+        }
+
+        if (typeof onComment === 'function') {
+            parser.forEachToken((type, start, end) => {
+                if (type === Comment) {
+                    const loc = parser.getLocation(start, end);
+                    const value = cmpStr(source, end - 2, end, '*/')
+                        ? source.slice(start + 2, end - 2)
+                        : source.slice(start + 2, end);
+
+                    onComment(value, loc);
+                }
+            });
+        }
+
+        const ast = parser.context[context].call(parser, options);
+
+        if (!parser.eof) {
+            parser.error();
+        }
+
+        return ast;
+    };
+
+    return Object.assign(parse, {
+        SyntaxError,
+        config: parser.config
+    });
+};

node_modules/css-tree/lib/parser/index.js

@@ -0,0 +1,4 @@
+import { createParser } from './create.js';
+import config from '../syntax/config/parser.js';
+
+export default createParser(config);

node_modules/css-tree/lib/parser/parse-selector.js

@@ -0,0 +1,4 @@
+import { createParser } from './create.js';
+import config from '../syntax/config/parser-selector.js';
+
+export default createParser(config);

node_modules/css-tree/lib/parser/sequence.js

@@ -0,0 +1,43 @@
+import { WhiteSpace, Comment } from '../tokenizer/index.js';
+
+export function readSequence(recognizer) {
+    const children = this.createList();
+    let space = false;
+    const context = {
+        recognizer
+    };
+
+    while (!this.eof) {
+        switch (this.tokenType) {
+            case Comment:
+                this.next();
+                continue;
+
+            case WhiteSpace:
+                space = true;
+                this.next();
+                continue;
+        }
+
+        let child = recognizer.getNode.call(this, context);
+
+        if (child === undefined) {
+            break;
+        }
+
+        if (space) {
+            if (recognizer.onWhiteSpace) {
+                recognizer.onWhiteSpace.call(this, child, children, context);
+            }
+            space = false;
+        }
+
+        children.push(child);
+    }
+
+    if (space && recognizer.onWhiteSpace) {
+        recognizer.onWhiteSpace.call(this, null, children, context);
+    }
+
+    return children;
+};

node_modules/css-tree/lib/syntax/atrule/font-face.js

@@ -0,0 +1,8 @@
+export default {
+    parse: {
+        prelude: null,
+        block() {
+            return this.Block(true);
+        }
+    }
+};

node_modules/css-tree/lib/syntax/atrule/import.js

@@ -0,0 +1,39 @@
+import {
+    String as StringToken,
+    Ident,
+    Url,
+    Function as FunctionToken,
+    LeftParenthesis
+} from '../../tokenizer/index.js';
+
+export default {
+    parse: {
+        prelude() {
+            const children = this.createList();
+
+            this.skipSC();
+
+            switch (this.tokenType) {
+                case StringToken:
+                    children.push(this.String());
+                    break;
+
+                case Url:
+                case FunctionToken:
+                    children.push(this.Url());
+                    break;
+
+                default:
+                    this.error('String or url() is expected');
+            }
+
+            if (this.lookupNonWSType(0) === Ident ||
+                this.lookupNonWSType(0) === LeftParenthesis) {
+                children.push(this.MediaQueryList());
+            }
+
+            return children;
+        },
+        block: null
+    }
+};

node_modules/css-tree/lib/syntax/atrule/index.js

@@ -0,0 +1,13 @@
+import fontFace from './font-face.js';
+import importAtrule from './import.js';
+import media from './media.js';
+import page from './page.js';
+import supports from './supports.js';
+
+export default {
+    'font-face': fontFace,
+    'import': importAtrule,
+    media,
+    page,
+    supports
+};

node_modules/css-tree/lib/syntax/atrule/media.js

@@ -0,0 +1,12 @@
+export default {
+    parse: {
+        prelude() {
+            return this.createSingleNodeList(
+                this.MediaQueryList()
+            );
+        },
+        block() {
+            return this.Block(false);
+        }
+    }
+};

node_modules/css-tree/lib/syntax/atrule/page.js

@@ -0,0 +1,12 @@
+export default {
+    parse: {
+        prelude() {
+            return this.createSingleNodeList(
+                this.SelectorList()
+            );
+        },
+        block() {
+            return this.Block(true);
+        }
+    }
+};

node_modules/css-tree/lib/syntax/atrule/supports.js

@@ -0,0 +1,80 @@
+import {
+    WhiteSpace,
+    Comment,
+    Ident,
+    Function,
+    Colon,
+    LeftParenthesis
+} from '../../tokenizer/index.js';
+
+function consumeRaw() {
+    return this.createSingleNodeList(
+        this.Raw(this.tokenIndex, null, false)
+    );
+}
+
+function parentheses() {
+    this.skipSC();
+
+    if (this.tokenType === Ident &&
+        this.lookupNonWSType(1) === Colon) {
+        return this.createSingleNodeList(
+            this.Declaration()
+        );
+    }
+
+    return readSequence.call(this);
+}
+
+function readSequence() {
+    const children = this.createList();
+    let child;
+
+    this.skipSC();
+
+    scan:
+    while (!this.eof) {
+        switch (this.tokenType) {
+            case Comment:
+            case WhiteSpace:
+                this.next();
+                continue;
+
+            case Function:
+                child = this.Function(consumeRaw, this.scope.AtrulePrelude);
+                break;
+
+            case Ident:
+                child = this.Identifier();
+                break;
+
+            case LeftParenthesis:
+                child = this.Parentheses(parentheses, this.scope.AtrulePrelude);
+                break;
+
+            default:
+                break scan;
+        }
+
+        children.push(child);
+    }
+
+    return children;
+}
+
+export default {
+    parse: {
+        prelude() {
+            const children = readSequence.call(this);
+
+            if (this.getFirstListNode(children) === null) {
+                this.error('Condition is expected');
+            }
+
+            return children;
+        },
+        block() {
+            return this.Block(false);
+        }
+    }
+};

node_modules/css-tree/lib/syntax/config/generator.js

@@ -0,0 +1,5 @@
+import * as node from '../node/index-generate.js';
+
+export default {
+    node
+};

node_modules/css-tree/lib/syntax/config/lexer.js

@@ -0,0 +1,8 @@
+import definitions from '../../data.js';
+import * as node from '../node/index.js';
+
+export default {
+    generic: true,
+    ...definitions,
+    node
+};

node_modules/css-tree/lib/syntax/config/mix.js

@@ -0,0 +1,138 @@
+const { hasOwnProperty } = Object.prototype;
+const shape = {
+    generic: true,
+    types: appendOrAssign,
+    atrules: {
+        prelude: appendOrAssignOrNull,
+        descriptors: appendOrAssignOrNull
+    },
+    properties: appendOrAssign,
+    parseContext: assign,
+    scope: deepAssign,
+    atrule: ['parse'],
+    pseudo: ['parse'],
+    node: ['name', 'structure', 'parse', 'generate', 'walkContext']
+};
+
+function isObject(value) {
+    return value && value.constructor === Object;
+}
+
+function copy(value) {
+    return isObject(value)
+        ? { ...value }
+        : value;
+}
+
+function assign(dest, src) {
+    return Object.assign(dest, src);
+}
+
+function deepAssign(dest, src) {
+    for (const key in src) {
+        if (hasOwnProperty.call(src, key)) {
+            if (isObject(dest[key])) {
+                deepAssign(dest[key], src[key]);
+            } else {
+                dest[key] = copy(src[key]);
+            }
+        }
+    }
+
+    return dest;
+}
+
+function append(a, b) {
+    if (typeof b === 'string' && /^\s*\|/.test(b)) {
+        return typeof a === 'string'
+            ? a + b
+            : b.replace(/^\s*\|\s*/, '');
+    }
+
+    return b || null;
+}
+
+function appendOrAssign(a, b) {
+    if (typeof b === 'string') {
+        return append(a, b);
+    }
+
+    const result = { ...a };
+    for (let key in b) {
+        if (hasOwnProperty.call(b, key)) {
+            result[key] = append(hasOwnProperty.call(a, key) ? a[key] : undefined, b[key]);
+        }
+    }
+
+    return result;
+}
+
+function appendOrAssignOrNull(a, b) {
+    const result = appendOrAssign(a, b);
+
+    return !isObject(result) || Object.keys(result).length
+        ? result
+        : null;
+}
+
+function mix(dest, src, shape) {
+    for (const key in shape) {
+        if (hasOwnProperty.call(shape, key) === false) {
+            continue;
+        }
+
+        if (shape[key] === true) {
+            if (hasOwnProperty.call(src, key)) {
+                dest[key] = copy(src[key]);
+            }
+        } else if (shape[key]) {
+            if (typeof shape[key] === 'function') {
+                const fn = shape[key];
+                dest[key] = fn({}, dest[key]);
+                dest[key] = fn(dest[key] || {}, src[key]);
+            } else if (isObject(shape[key])) {
+                const result = {};
+
+                for (let name in dest[key]) {
+                    result[name] = mix({}, dest[key][name], shape[key]);
+                }
+
+                for (let name in src[key]) {
+                    result[name] = mix(result[name] || {}, src[key][name], shape[key]);
+                }
+
+                dest[key] = result;
+            } else if (Array.isArray(shape[key])) {
+                const res = {};
+                const innerShape = shape[key].reduce(function(s, k) {
+                    s[k] = true;
+                    return s;
+                }, {});
+
+                for (const [name, value] of Object.entries(dest[key] || {})) {
+                    res[name] = {};
+                    if (value) {
+                        mix(res[name], value, innerShape);
+                    }
+                }
+
+                for (const name in src[key]) {
+                    if (hasOwnProperty.call(src[key], name)) {
+                        if (!res[name]) {
+                            res[name] = {};
+                        }
+
+                        if (src[key] && src[key][name]) {
+                            mix(res[name], src[key][name], innerShape);
+                        }
+                    }
+                }
+
+                dest[key] = res;
+            }
+        }
+    }
+    return dest;
+}
+
+export default (dest, src) => mix(dest, src, shape);

node_modules/css-tree/lib/syntax/config/parser-selector.js

@@ -0,0 +1,15 @@
+import { Selector } from '../scope/index.js';
+import pseudo from '../pseudo/index.js';
+import * as node from '../node/index-parse-selector.js';
+
+export default {
+    parseContext: {
+        default: 'SelectorList',
+        selectorList: 'SelectorList',
+        selector: 'Selector'
+    },
+    scope: { Selector },
+    atrule: {},
+    pseudo,
+    node
+};

node_modules/css-tree/lib/syntax/config/parser.js

@@ -0,0 +1,30 @@
+import * as scope from '../scope/index.js';
+import atrule from '../atrule/index.js';
+import pseudo from '../pseudo/index.js';
+import * as node from '../node/index-parse.js';
+
+export default {
+    parseContext: {
+        default: 'StyleSheet',
+        stylesheet: 'StyleSheet',
+        atrule: 'Atrule',
+        atrulePrelude(options) {
+            return this.AtrulePrelude(options.atrule ? String(options.atrule) : null);
+        },
+        mediaQueryList: 'MediaQueryList',
+        mediaQuery: 'MediaQuery',
+        rule: 'Rule',
+        selectorList: 'SelectorList',
+        selector: 'Selector',
+        block() {
+            return this.Block(true);
+        },
+        declarationList: 'DeclarationList',
+        declaration: 'Declaration',
+        value: 'Value'
+    },
+    scope,
+    atrule,
+    pseudo,
+    node
+};

node_modules/css-tree/lib/syntax/config/walker.js

@@ -0,0 +1,5 @@
+import * as node from '../node/index.js';
+
+export default {
+    node
+};

node_modules/css-tree/lib/syntax/create.js

@@ -0,0 +1,53 @@
+import { tokenize } from '../tokenizer/index.js';
+import { createParser } from '../parser/create.js';
+import { createGenerator } from '../generator/create.js';
+import { createConvertor } from '../convertor/create.js';
+import { createWalker } from '../walker/create.js';
+import { Lexer } from '../lexer/Lexer.js';
+import mix from './config/mix.js';
+
+function createSyntax(config) {
+    const parse = createParser(config);
+    const walk = createWalker(config);
+    const generate = createGenerator(config);
+    const { fromPlainObject, toPlainObject } = createConvertor(walk);
+
+    const syntax = {
+        lexer: null,
+        createLexer: config => new Lexer(config, syntax, syntax.lexer.structure),
+
+        tokenize,
+        parse,
+        generate,
+
+        walk,
+        find: walk.find,
+        findLast: walk.findLast,
+        findAll: walk.findAll,
+
+        fromPlainObject,
+        toPlainObject,
+
+        fork(extension) {
+            const base = mix({}, config); // copy of config
+
+            return createSyntax(
+                typeof extension === 'function'
+                    ? extension(base, Object.assign)
+                    : mix(base, extension)
+            );
+        }
+    };
+
+    syntax.lexer = new Lexer({
+        generic: true,
+        types: config.types,
+        atrules: config.atrules,
+        properties: config.properties,
+        node: config.node
+    }, syntax);
+
+    return syntax;
+};
+
+export default config => createSyntax(mix({}, config));

node_modules/css-tree/lib/syntax/function/expression.js

@@ -0,0 +1,7 @@
+// legacy IE function
+// expression( <any-value> )
+export default function() {
+    return this.createSingleNodeList(
+        this.Raw(this.tokenIndex, null, false)
+    );
+}

node_modules/css-tree/lib/syntax/function/var.js

@@ -0,0 +1,39 @@
+import { Comma, WhiteSpace } from '../../tokenizer/index.js';
+
+// var( <ident> , <value>? )
+export default function() {
+    const children = this.createList();
+
+    this.skipSC();
+
+    // NOTE: Don't check more than a first argument is an ident, rest checks are for lexer
+    children.push(this.Identifier());
+
+    this.skipSC();
+
+    if (this.tokenType === Comma) {
+        children.push(this.Operator());
+
+        const startIndex = this.tokenIndex;
+        const value = this.parseCustomProperty
+            ? this.Value(null)
+            : this.Raw(this.tokenIndex, this.consumeUntilExclamationMarkOrSemicolon, false);
+
+        if (value.type === 'Value' && value.children.isEmpty) {
+            for (let offset = startIndex - this.tokenIndex; offset <= 0; offset++) {
+                if (this.lookupType(offset) === WhiteSpace) {
+                    value.children.appendData({
+                        type: 'WhiteSpace',
+                        loc: null,
+                        value: ' '
+                    });
+                    break;
+                }
+            }
+        }
+
+        children.push(value);
+    }
+
+    return children;
+};

node_modules/css-tree/lib/syntax/index.js

@@ -0,0 +1,10 @@
+import createSyntax from './create.js';
+import lexerConfig from './config/lexer.js';
+import parserConfig from './config/parser.js';
+import walkerConfig from './config/walker.js';
+
+export default createSyntax({
+    ...lexerConfig,
+    ...parserConfig,
+    ...walkerConfig
+});

node_modules/css-tree/lib/syntax/node/AnPlusB.js

@@ -0,0 +1,292 @@
+import {
+    isDigit,
+    WhiteSpace,
+    Comment,
+    Ident,
+    Number,
+    Dimension
+} from '../../tokenizer/index.js';
+
+const PLUSSIGN = 0x002B;    // U+002B PLUS SIGN (+)
+const HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
+const N = 0x006E;           // U+006E LATIN SMALL LETTER N (n)
+const DISALLOW_SIGN = true;
+const ALLOW_SIGN = false;
+
+function checkInteger(offset, disallowSign) {
+    let pos = this.tokenStart + offset;
+    const code = this.charCodeAt(pos);
+
+    if (code === PLUSSIGN || code === HYPHENMINUS) {
+        if (disallowSign) {
+            this.error('Number sign is not allowed');
+        }
+        pos++;
+    }
+
+    for (; pos < this.tokenEnd; pos++) {
+        if (!isDigit(this.charCodeAt(pos))) {
+            this.error('Integer is expected', pos);
+        }
+    }
+}
+
+function checkTokenIsInteger(disallowSign) {
+    return checkInteger.call(this, 0, disallowSign);
+}
+
+function expectCharCode(offset, code) {
+    if (!this.cmpChar(this.tokenStart + offset, code)) {
+        let msg = '';
+
+        switch (code) {
+            case N:
+                msg = 'N is expected';
+                break;
+            case HYPHENMINUS:
+                msg = 'HyphenMinus is expected';
+                break;
+        }
+
+        this.error(msg, this.tokenStart + offset);
+    }
+}
+
+// ... <signed-integer>
+// ... ['+' | '-'] <signless-integer>
+function consumeB() {
+    let offset = 0;
+    let sign = 0;
+    let type = this.tokenType;
+
+    while (type === WhiteSpace || type === Comment) {
+        type = this.lookupType(++offset);
+    }
+
+    if (type !== Number) {
+        if (this.isDelim(PLUSSIGN, offset) ||
+            this.isDelim(HYPHENMINUS, offset)) {
+            sign = this.isDelim(PLUSSIGN, offset) ? PLUSSIGN : HYPHENMINUS;
+
+            do {
+                type = this.lookupType(++offset);
+            } while (type === WhiteSpace || type === Comment);
+
+            if (type !== Number) {
+                this.skip(offset);
+                checkTokenIsInteger.call(this, DISALLOW_SIGN);
+            }
+        } else {
+            return null;
+        }
+    }
+
+    if (offset > 0) {
+        this.skip(offset);
+    }
+
+    if (sign === 0) {
+        type = this.charCodeAt(this.tokenStart);
+        if (type !== PLUSSIGN && type !== HYPHENMINUS) {
+            this.error('Number sign is expected');
+        }
+    }
+
+    checkTokenIsInteger.call(this, sign !== 0);
+    return sign === HYPHENMINUS ? '-' + this.consume(Number) : this.consume(Number);
+}
+
+// An+B microsyntax https://www.w3.org/TR/css-syntax-3/#anb
+export const name = 'AnPlusB';
+export const structure = {
+    a: [String, null],
+    b: [String, null]
+};
+
+export function parse() {
+    /* eslint-disable brace-style*/
+    const start = this.tokenStart;
+    let a = null;
+    let b = null;
+
+    // <integer>
+    if (this.tokenType === Number) {
+        checkTokenIsInteger.call(this, ALLOW_SIGN);
+        b = this.consume(Number);
+    }
+
+    // -n
+    // -n <signed-integer>
+    // -n ['+' | '-'] <signless-integer>
+    // -n- <signless-integer>
+    // <dashndashdigit-ident>
+    else if (this.tokenType === Ident && this.cmpChar(this.tokenStart, HYPHENMINUS)) {
+        a = '-1';
+
+        expectCharCode.call(this, 1, N);
+
+        switch (this.tokenEnd - this.tokenStart) {
+            // -n
+            // -n <signed-integer>
+            // -n ['+' | '-'] <signless-integer>
+            case 2:
+                this.next();
+                b = consumeB.call(this);
+                break;
+
+            // -n- <signless-integer>
+            case 3:
+                expectCharCode.call(this, 2, HYPHENMINUS);
+
+                this.next();
+                this.skipSC();
+
+                checkTokenIsInteger.call(this, DISALLOW_SIGN);
+
+                b = '-' + this.consume(Number);
+                break;
+
+            // <dashndashdigit-ident>
+            default:
+                expectCharCode.call(this, 2, HYPHENMINUS);
+                checkInteger.call(this, 3, DISALLOW_SIGN);
+                this.next();
+
+                b = this.substrToCursor(start + 2);
+        }
+    }
+
+    // '+'? n
+    // '+'? n <signed-integer>
+    // '+'? n ['+' | '-'] <signless-integer>
+    // '+'? n- <signless-integer>
+    // '+'? <ndashdigit-ident>
+    else if (this.tokenType === Ident || (this.isDelim(PLUSSIGN) && this.lookupType(1) === Ident)) {
+        let sign = 0;
+        a = '1';
+
+        // just ignore a plus
+        if (this.isDelim(PLUSSIGN)) {
+            sign = 1;
+            this.next();
+        }
+
+        expectCharCode.call(this, 0, N);
+
+        switch (this.tokenEnd - this.tokenStart) {
+            // '+'? n
+            // '+'? n <signed-integer>
+            // '+'? n ['+' | '-'] <signless-integer>
+            case 1:
+                this.next();
+                b = consumeB.call(this);
+                break;
+
+            // '+'? n- <signless-integer>
+            case 2:
+                expectCharCode.call(this, 1, HYPHENMINUS);
+
+                this.next();
+                this.skipSC();
+
+                checkTokenIsInteger.call(this, DISALLOW_SIGN);
+
+                b = '-' + this.consume(Number);
+                break;
+
+            // '+'? <ndashdigit-ident>
+            default:
+                expectCharCode.call(this, 1, HYPHENMINUS);
+                checkInteger.call(this, 2, DISALLOW_SIGN);
+                this.next();
+
+                b = this.substrToCursor(start + sign + 1);
+        }
+    }
+
+    // <ndashdigit-dimension>
+    // <ndash-dimension> <signless-integer>
+    // <n-dimension>
+    // <n-dimension> <signed-integer>
+    // <n-dimension> ['+' | '-'] <signless-integer>
+    else if (this.tokenType === Dimension) {
+        const code = this.charCodeAt(this.tokenStart);
+        const sign = code === PLUSSIGN || code === HYPHENMINUS;
+        let i = this.tokenStart + sign;
+
+        for (; i < this.tokenEnd; i++) {
+            if (!isDigit(this.charCodeAt(i))) {
+                break;
+            }
+        }
+
+        if (i === this.tokenStart + sign) {
+            this.error('Integer is expected', this.tokenStart + sign);
+        }
+
+        expectCharCode.call(this, i - this.tokenStart, N);
+        a = this.substring(start, i);
+
+        // <n-dimension>
+        // <n-dimension> <signed-integer>
+        // <n-dimension> ['+' | '-'] <signless-integer>
+        if (i + 1 === this.tokenEnd) {
+            this.next();
+            b = consumeB.call(this);
+        } else {
+            expectCharCode.call(this, i - this.tokenStart + 1, HYPHENMINUS);
+
+            // <ndash-dimension> <signless-integer>
+            if (i + 2 === this.tokenEnd) {
+                this.next();
+                this.skipSC();
+                checkTokenIsInteger.call(this, DISALLOW_SIGN);
+                b = '-' + this.consume(Number);
+            }
+            // <ndashdigit-dimension>
+            else {
+                checkInteger.call(this, i - this.tokenStart + 2, DISALLOW_SIGN);
+                this.next();
+                b = this.substrToCursor(i + 1);
+            }
+        }
+    } else {
+        this.error();
+    }
+
+    if (a !== null && a.charCodeAt(0) === PLUSSIGN) {
+        a = a.substr(1);
+    }
+
+    if (b !== null && b.charCodeAt(0) === PLUSSIGN) {
+        b = b.substr(1);
+    }
+
+    return {
+        type: 'AnPlusB',
+        loc: this.getLocation(start, this.tokenStart),
+        a,
+        b
+    };
+}
+
+export function generate(node) {
+    if (node.a) {
+        const a =
+            node.a === '+1' && 'n' ||
+            node.a ===  '1' && 'n' ||
+            node.a === '-1' && '-n' ||
+            node.a + 'n';
+
+        if (node.b) {
+            const b = node.b[0] === '-' || node.b[0] === '+'
+                ? node.b
+                : '+' + node.b;
+            this.tokenize(a + b);
+        } else {
+            this.tokenize(a);
+        }
+    } else {
+        this.tokenize(node.b);
+    }
+}

node_modules/css-tree/lib/syntax/node/Atrule.js

@@ -0,0 +1,100 @@
+import {
+    AtKeyword,
+    Semicolon,
+    LeftCurlyBracket,
+    RightCurlyBracket
+} from '../../tokenizer/index.js';
+
+function consumeRaw(startToken) {
+    return this.Raw(startToken, this.consumeUntilLeftCurlyBracketOrSemicolon, true);
+}
+
+function isDeclarationBlockAtrule() {
+    for (let offset = 1, type; type = this.lookupType(offset); offset++) {
+        if (type === RightCurlyBracket) {
+            return true;
+        }
+
+        if (type === LeftCurlyBracket ||
+            type === AtKeyword) {
+            return false;
+        }
+    }
+
+    return false;
+}
+
+
+export const name = 'Atrule';
+export const walkContext = 'atrule';
+export const structure = {
+    name: String,
+    prelude: ['AtrulePrelude', 'Raw', null],
+    block: ['Block', null]
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    let name;
+    let nameLowerCase;
+    let prelude = null;
+    let block = null;
+
+    this.eat(AtKeyword);
+
+    name = this.substrToCursor(start + 1);
+    nameLowerCase = name.toLowerCase();
+    this.skipSC();
+
+    // parse prelude
+    if (this.eof === false &&
+        this.tokenType !== LeftCurlyBracket &&
+        this.tokenType !== Semicolon) {
+        if (this.parseAtrulePrelude) {
+            prelude = this.parseWithFallback(this.AtrulePrelude.bind(this, name), consumeRaw);
+        } else {
+            prelude = consumeRaw.call(this, this.tokenIndex);
+        }
+
+        this.skipSC();
+    }
+
+    switch (this.tokenType) {
+        case Semicolon:
+            this.next();
+            break;
+
+        case LeftCurlyBracket:
+            if (hasOwnProperty.call(this.atrule, nameLowerCase) &&
+                typeof this.atrule[nameLowerCase].block === 'function') {
+                block = this.atrule[nameLowerCase].block.call(this);
+            } else {
+                // TODO: should consume block content as Raw?
+                block = this.Block(isDeclarationBlockAtrule.call(this));
+            }
+
+            break;
+    }
+
+    return {
+        type: 'Atrule',
+        loc: this.getLocation(start, this.tokenStart),
+        name,
+        prelude,
+        block
+    };
+}
+
+export function generate(node) {
+    this.token(AtKeyword, '@' + node.name);
+
+    if (node.prelude !== null) {
+        this.node(node.prelude);
+    }
+
+    if (node.block) {
+        this.node(node.block);
+    } else {
+        this.token(Semicolon, ';');
+    }
+}

node_modules/css-tree/lib/syntax/node/AtrulePrelude.js

@@ -0,0 +1,47 @@
+import {
+    Semicolon,
+    LeftCurlyBracket
+} from '../../tokenizer/index.js';
+
+export const name = 'AtrulePrelude';
+export const walkContext = 'atrulePrelude';
+export const structure = {
+    children: [[]]
+};
+
+export function parse(name) {
+    let children = null;
+
+    if (name !== null) {
+        name = name.toLowerCase();
+    }
+
+    this.skipSC();
+
+    if (hasOwnProperty.call(this.atrule, name) &&
+        typeof this.atrule[name].prelude === 'function') {
+        // custom consumer
+        children = this.atrule[name].prelude.call(this);
+    } else {
+        // default consumer
+        children = this.readSequence(this.scope.AtrulePrelude);
+    }
+
+    this.skipSC();
+
+    if (this.eof !== true &&
+        this.tokenType !== LeftCurlyBracket &&
+        this.tokenType !== Semicolon) {
+        this.error('Semicolon or block is expected');
+    }
+
+    return {
+        type: 'AtrulePrelude',
+        loc: this.getLocationFromList(children),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node);
+}

node_modules/css-tree/lib/syntax/node/AttributeSelector.js

@@ -0,0 +1,147 @@
+import {
+    Ident,
+    String as StringToken,
+    Delim,
+    LeftSquareBracket,
+    RightSquareBracket
+} from '../../tokenizer/index.js';
+
+const DOLLARSIGN = 0x0024;       // U+0024 DOLLAR SIGN ($)
+const ASTERISK = 0x002A;         // U+002A ASTERISK (*)
+const EQUALSSIGN = 0x003D;       // U+003D EQUALS SIGN (=)
+const CIRCUMFLEXACCENT = 0x005E; // U+005E (^)
+const VERTICALLINE = 0x007C;     // U+007C VERTICAL LINE (|)
+const TILDE = 0x007E;            // U+007E TILDE (~)
+
+function getAttributeName() {
+    if (this.eof) {
+        this.error('Unexpected end of input');
+    }
+
+    const start = this.tokenStart;
+    let expectIdent = false;
+
+    if (this.isDelim(ASTERISK)) {
+        expectIdent = true;
+        this.next();
+    } else if (!this.isDelim(VERTICALLINE)) {
+        this.eat(Ident);
+    }
+
+    if (this.isDelim(VERTICALLINE)) {
+        if (this.charCodeAt(this.tokenStart + 1) !== EQUALSSIGN) {
+            this.next();
+            this.eat(Ident);
+        } else if (expectIdent) {
+            this.error('Identifier is expected', this.tokenEnd);
+        }
+    } else if (expectIdent) {
+        this.error('Vertical line is expected');
+    }
+
+    return {
+        type: 'Identifier',
+        loc: this.getLocation(start, this.tokenStart),
+        name: this.substrToCursor(start)
+    };
+}
+
+function getOperator() {
+    const start = this.tokenStart;
+    const code = this.charCodeAt(start);
+
+    if (code !== EQUALSSIGN &&        // =
+        code !== TILDE &&             // ~=
+        code !== CIRCUMFLEXACCENT &&  // ^=
+        code !== DOLLARSIGN &&        // $=
+        code !== ASTERISK &&          // *=
+        code !== VERTICALLINE         // |=
+    ) {
+        this.error('Attribute selector (=, ~=, ^=, $=, *=, |=) is expected');
+    }
+
+    this.next();
+
+    if (code !== EQUALSSIGN) {
+        if (!this.isDelim(EQUALSSIGN)) {
+            this.error('Equal sign is expected');
+        }
+
+        this.next();
+    }
+
+    return this.substrToCursor(start);
+}
+
+// '[' <wq-name> ']'
+// '[' <wq-name> <attr-matcher> [ <string-token> | <ident-token> ] <attr-modifier>? ']'
+export const name = 'AttributeSelector';
+export const structure = {
+    name: 'Identifier',
+    matcher: [String, null],
+    value: ['String', 'Identifier', null],
+    flags: [String, null]
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    let name;
+    let matcher = null;
+    let value = null;
+    let flags = null;
+
+    this.eat(LeftSquareBracket);
+    this.skipSC();
+
+    name = getAttributeName.call(this);
+    this.skipSC();
+
+    if (this.tokenType !== RightSquareBracket) {
+        // avoid case `[name i]`
+        if (this.tokenType !== Ident) {
+            matcher = getOperator.call(this);
+
+            this.skipSC();
+
+            value = this.tokenType === StringToken
+                ? this.String()
+                : this.Identifier();
+
+            this.skipSC();
+        }
+
+        // attribute flags
+        if (this.tokenType === Ident) {
+            flags = this.consume(Ident);
+
+            this.skipSC();
+        }
+    }
+
+    this.eat(RightSquareBracket);
+
+    return {
+        type: 'AttributeSelector',
+        loc: this.getLocation(start, this.tokenStart),
+        name,
+        matcher,
+        value,
+        flags
+    };
+}
+
+export function generate(node) {
+    this.token(Delim, '[');
+    this.node(node.name);
+
+    if (node.matcher !== null) {
+        this.tokenize(node.matcher);
+        this.node(node.value);
+    }
+
+    if (node.flags !== null) {
+        this.token(Ident, node.flags);
+    }
+
+    this.token(Delim, ']');
+}

node_modules/css-tree/lib/syntax/node/Block.js

@@ -0,0 +1,89 @@
+import {
+    WhiteSpace,
+    Comment,
+    Semicolon,
+    AtKeyword,
+    LeftCurlyBracket,
+    RightCurlyBracket
+} from '../../tokenizer/index.js';
+
+function consumeRaw(startToken) {
+    return this.Raw(startToken, null, true);
+}
+function consumeRule() {
+    return this.parseWithFallback(this.Rule, consumeRaw);
+}
+function consumeRawDeclaration(startToken) {
+    return this.Raw(startToken, this.consumeUntilSemicolonIncluded, true);
+}
+function consumeDeclaration() {
+    if (this.tokenType === Semicolon) {
+        return consumeRawDeclaration.call(this, this.tokenIndex);
+    }
+
+    const node = this.parseWithFallback(this.Declaration, consumeRawDeclaration);
+
+    if (this.tokenType === Semicolon) {
+        this.next();
+    }
+
+    return node;
+}
+
+export const name = 'Block';
+export const walkContext = 'block';
+export const structure = {
+    children: [[
+        'Atrule',
+        'Rule',
+        'Declaration'
+    ]]
+};
+
+export function parse(isDeclaration) {
+    const consumer = isDeclaration ? consumeDeclaration : consumeRule;
+    const start = this.tokenStart;
+    let children = this.createList();
+
+    this.eat(LeftCurlyBracket);
+
+    scan:
+    while (!this.eof) {
+        switch (this.tokenType) {
+            case RightCurlyBracket:
+                break scan;
+
+            case WhiteSpace:
+            case Comment:
+                this.next();
+                break;
+
+            case AtKeyword:
+                children.push(this.parseWithFallback(this.Atrule, consumeRaw));
+                break;
+
+            default:
+                children.push(consumer.call(this));
+        }
+    }
+
+    if (!this.eof) {
+        this.eat(RightCurlyBracket);
+    }
+
+    return {
+        type: 'Block',
+        loc: this.getLocation(start, this.tokenStart),
+        children
+    };
+}
+
+export function generate(node) {
+    this.token(LeftCurlyBracket, '{');
+    this.children(node, prev => {
+        if (prev.type === 'Declaration') {
+            this.token(Semicolon, ';');
+        }
+    });
+    this.token(RightCurlyBracket, '}');
+}

node_modules/css-tree/lib/syntax/node/Brackets.js

@@ -0,0 +1,35 @@
+import {
+    Delim,
+    LeftSquareBracket,
+    RightSquareBracket
+} from '../../tokenizer/index.js';
+
+export const name = 'Brackets';
+export const structure = {
+    children: [[]]
+};
+
+export function parse(readSequence, recognizer) {
+    const start = this.tokenStart;
+    let children = null;
+
+    this.eat(LeftSquareBracket);
+
+    children = readSequence.call(this, recognizer);
+
+    if (!this.eof) {
+        this.eat(RightSquareBracket);
+    }
+
+    return {
+        type: 'Brackets',
+        loc: this.getLocation(start, this.tokenStart),
+        children
+    };
+}
+
+export function generate(node) {
+    this.token(Delim, '[');
+    this.children(node);
+    this.token(Delim, ']');
+}

node_modules/css-tree/lib/syntax/node/CDC.js

@@ -0,0 +1,19 @@
+import { CDC } from '../../tokenizer/index.js';
+
+export const name = 'CDC';
+export const structure = [];
+
+export function parse() {
+    const start = this.tokenStart;
+
+    this.eat(CDC); // -->
+
+    return {
+        type: 'CDC',
+        loc: this.getLocation(start, this.tokenStart)
+    };
+}
+
+export function generate() {
+    this.token(CDC, '-->');
+}

node_modules/css-tree/lib/syntax/node/CDO.js

@@ -0,0 +1,19 @@
+import { CDO } from '../../tokenizer/index.js';
+
+export const name = 'CDO';
+export const structure = [];
+
+export function parse() {
+    const start = this.tokenStart;
+
+    this.eat(CDO); // <!--
+
+    return {
+        type: 'CDO',
+        loc: this.getLocation(start, this.tokenStart)
+    };
+}
+
+export function generate() {
+    this.token(CDO, '<!--');
+}

node_modules/css-tree/lib/syntax/node/ClassSelector.js

@@ -0,0 +1,24 @@
+import { Delim, Ident } from '../../tokenizer/index.js';
+
+const FULLSTOP = 0x002E; // U+002E FULL STOP (.)
+
+// '.' ident
+export const name = 'ClassSelector';
+export const structure = {
+    name: String
+};
+
+export function parse() {
+    this.eatDelim(FULLSTOP);
+
+    return {
+        type: 'ClassSelector',
+        loc: this.getLocation(this.tokenStart - 1, this.tokenEnd),
+        name: this.consume(Ident)
+    };
+}
+
+export function generate(node) {
+    this.token(Delim, '.');
+    this.token(Ident, node.name);
+}

node_modules/css-tree/lib/syntax/node/Combinator.js

@@ -0,0 +1,54 @@
+import { WhiteSpace, Delim } from '../../tokenizer/index.js';
+
+const PLUSSIGN = 0x002B;        // U+002B PLUS SIGN (+)
+const SOLIDUS = 0x002F;         // U+002F SOLIDUS (/)
+const GREATERTHANSIGN = 0x003E; // U+003E GREATER-THAN SIGN (>)
+const TILDE = 0x007E;           // U+007E TILDE (~)
+
+export const name = 'Combinator';
+export const structure = {
+    name: String
+};
+
+// + | > | ~ | /deep/
+export function parse() {
+    const start = this.tokenStart;
+    let name;
+
+    switch (this.tokenType) {
+        case WhiteSpace:
+            name = ' ';
+            break;
+
+        case Delim:
+            switch (this.charCodeAt(this.tokenStart)) {
+                case GREATERTHANSIGN:
+                case PLUSSIGN:
+                case TILDE:
+                    this.next();
+                    break;
+
+                case SOLIDUS:
+                    this.next();
+                    this.eatIdent('deep');
+                    this.eatDelim(SOLIDUS);
+                    break;
+
+                default:
+                    this.error('Combinator is expected');
+            }
+
+            name = this.substrToCursor(start);
+            break;
+    }
+
+    return {
+        type: 'Combinator',
+        loc: this.getLocation(start, this.tokenStart),
+        name
+    };
+}
+
+export function generate(node) {
+    this.tokenize(node.name);
+}

node_modules/css-tree/lib/syntax/node/Comment.js

@@ -0,0 +1,33 @@
+import { Comment } from '../../tokenizer/index.js';
+
+const ASTERISK = 0x002A;        // U+002A ASTERISK (*)
+const SOLIDUS = 0x002F;         // U+002F SOLIDUS (/)
+
+
+export const name = 'Comment';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    let end = this.tokenEnd;
+
+    this.eat(Comment);
+
+    if ((end - start + 2) >= 2 &&
+        this.charCodeAt(end - 2) === ASTERISK &&
+        this.charCodeAt(end - 1) === SOLIDUS) {
+        end -= 2;
+    }
+
+    return {
+        type: 'Comment',
+        loc: this.getLocation(start, this.tokenStart),
+        value: this.substring(start + 2, end)
+    };
+}
+
+export function generate(node) {
+    this.token(Comment, '/*' + node.value + '*/');
+}

node_modules/css-tree/lib/syntax/node/Declaration.js

@@ -0,0 +1,165 @@
+import { isCustomProperty } from '../../utils/names.js';
+import {
+    Ident,
+    Hash,
+    Colon,
+    Semicolon,
+    Delim,
+    WhiteSpace
+} from '../../tokenizer/index.js';
+
+const EXCLAMATIONMARK = 0x0021; // U+0021 EXCLAMATION MARK (!)
+const NUMBERSIGN = 0x0023;      // U+0023 NUMBER SIGN (#)
+const DOLLARSIGN = 0x0024;      // U+0024 DOLLAR SIGN ($)
+const AMPERSAND = 0x0026;       // U+0026 AMPERSAND (&)
+const ASTERISK = 0x002A;        // U+002A ASTERISK (*)
+const PLUSSIGN = 0x002B;        // U+002B PLUS SIGN (+)
+const SOLIDUS = 0x002F;         // U+002F SOLIDUS (/)
+
+function consumeValueRaw(startToken) {
+    return this.Raw(startToken, this.consumeUntilExclamationMarkOrSemicolon, true);
+}
+
+function consumeCustomPropertyRaw(startToken) {
+    return this.Raw(startToken, this.consumeUntilExclamationMarkOrSemicolon, false);
+}
+
+function consumeValue() {
+    const startValueToken = this.tokenIndex;
+    const value = this.Value();
+
+    if (value.type !== 'Raw' &&
+        this.eof === false &&
+        this.tokenType !== Semicolon &&
+        this.isDelim(EXCLAMATIONMARK) === false &&
+        this.isBalanceEdge(startValueToken) === false) {
+        this.error();
+    }
+
+    return value;
+}
+
+export const name = 'Declaration';
+export const walkContext = 'declaration';
+export const structure = {
+    important: [Boolean, String],
+    property: String,
+    value: ['Value', 'Raw']
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    const startToken = this.tokenIndex;
+    const property = readProperty.call(this);
+    const customProperty = isCustomProperty(property);
+    const parseValue = customProperty ? this.parseCustomProperty : this.parseValue;
+    const consumeRaw = customProperty ? consumeCustomPropertyRaw : consumeValueRaw;
+    let important = false;
+    let value;
+
+    this.skipSC();
+    this.eat(Colon);
+
+    const valueStart = this.tokenIndex;
+
+    if (!customProperty) {
+        this.skipSC();
+    }
+
+    if (parseValue) {
+        value = this.parseWithFallback(consumeValue, consumeRaw);
+    } else {
+        value = consumeRaw.call(this, this.tokenIndex);
+    }
+
+    if (customProperty && value.type === 'Value' && value.children.isEmpty) {
+        for (let offset = valueStart - this.tokenIndex; offset <= 0; offset++) {
+            if (this.lookupType(offset) === WhiteSpace) {
+                value.children.appendData({
+                    type: 'WhiteSpace',
+                    loc: null,
+                    value: ' '
+                });
+                break;
+            }
+        }
+    }
+
+    if (this.isDelim(EXCLAMATIONMARK)) {
+        important = getImportant.call(this);
+        this.skipSC();
+    }
+
+    // Do not include semicolon to range per spec
+    // https://drafts.csswg.org/css-syntax/#declaration-diagram
+
+    if (this.eof === false &&
+        this.tokenType !== Semicolon &&
+        this.isBalanceEdge(startToken) === false) {
+        this.error();
+    }
+
+    return {
+        type: 'Declaration',
+        loc: this.getLocation(start, this.tokenStart),
+        important,
+        property,
+        value
+    };
+}
+
+export function generate(node) {
+    this.token(Ident, node.property);
+    this.token(Colon, ':');
+    this.node(node.value);
+
+    if (node.important) {
+        this.token(Delim, '!');
+        this.token(Ident, node.important === true ? 'important' : node.important);
+    }
+}
+
+function readProperty() {
+    const start = this.tokenStart;
+
+    // hacks
+    if (this.tokenType === Delim) {
+        switch (this.charCodeAt(this.tokenStart)) {
+            case ASTERISK:
+            case DOLLARSIGN:
+            case PLUSSIGN:
+            case NUMBERSIGN:
+            case AMPERSAND:
+                this.next();
+                break;
+
+            // TODO: not sure we should support this hack
+            case SOLIDUS:
+                this.next();
+                if (this.isDelim(SOLIDUS)) {
+                    this.next();
+                }
+                break;
+        }
+    }
+
+    if (this.tokenType === Hash) {
+        this.eat(Hash);
+    } else {
+        this.eat(Ident);
+    }
+
+    return this.substrToCursor(start);
+}
+
+// ! ws* important
+function getImportant() {
+    this.eat(Delim);
+    this.skipSC();
+
+    const important = this.consume(Ident);
+
+    // store original value in case it differ from `important`
+    // for better original source restoring and hacks like `!ie` support
+    return important === 'important' ? true : important;
+}

node_modules/css-tree/lib/syntax/node/DeclarationList.js

@@ -0,0 +1,49 @@
+import {
+    WhiteSpace,
+    Comment,
+    Semicolon
+} from '../../tokenizer/index.js';
+
+function consumeRaw(startToken) {
+    return this.Raw(startToken, this.consumeUntilSemicolonIncluded, true);
+}
+
+export const name = 'DeclarationList';
+export const structure = {
+    children: [[
+        'Declaration'
+    ]]
+};
+
+export function parse() {
+    const children = this.createList();
+
+    scan:
+    while (!this.eof) {
+        switch (this.tokenType) {
+            case WhiteSpace:
+            case Comment:
+            case Semicolon:
+                this.next();
+                break;
+
+            default:
+                children.push(this.parseWithFallback(this.Declaration, consumeRaw));
+        }
+    }
+
+    return {
+        type: 'DeclarationList',
+        loc: this.getLocationFromList(children),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node, prev => {
+        if (prev.type === 'Declaration') {
+            this.token(Semicolon, ';');
+        }
+    });
+}
+

node_modules/css-tree/lib/syntax/node/Dimension.js

@@ -0,0 +1,23 @@
+import { Dimension } from '../../tokenizer/index.js';
+
+export const name = 'Dimension';
+export const structure = {
+    value: String,
+    unit: String
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    const value = this.consumeNumber(Dimension);
+
+    return {
+        type: 'Dimension',
+        loc: this.getLocation(start, this.tokenStart),
+        value,
+        unit: this.substring(start + value.length, this.tokenStart)
+    };
+}
+
+export function generate(node) {
+    this.token(Dimension, node.value + node.unit);
+}

node_modules/css-tree/lib/syntax/node/Function.js

@@ -0,0 +1,41 @@
+import {
+    Function as FunctionToken,
+    RightParenthesis
+} from '../../tokenizer/index.js';
+
+
+export const name = 'Function';
+export const walkContext = 'function';
+export const structure = {
+    name: String,
+    children: [[]]
+};
+
+// <function-token> <sequence> )
+export function parse(readSequence, recognizer) {
+    const start = this.tokenStart;
+    const name = this.consumeFunctionName();
+    const nameLowerCase = name.toLowerCase();
+    let children;
+
+    children = recognizer.hasOwnProperty(nameLowerCase)
+        ? recognizer[nameLowerCase].call(this, recognizer)
+        : readSequence.call(this, recognizer);
+
+    if (!this.eof) {
+        this.eat(RightParenthesis);
+    }
+
+    return {
+        type: 'Function',
+        loc: this.getLocation(start, this.tokenStart),
+        name,
+        children
+    };
+}
+
+export function generate(node) {
+    this.token(FunctionToken, node.name + '(');
+    this.children(node);
+    this.token(RightParenthesis, ')');
+}

node_modules/css-tree/lib/syntax/node/Hash.js

@@ -0,0 +1,23 @@
+import { Hash } from '../../tokenizer/index.js';
+
+// '#' ident
+export const xxx = 'XXX';
+export const name = 'Hash';
+export const structure = {
+    value: String
+};
+export function parse() {
+    const start = this.tokenStart;
+
+    this.eat(Hash);
+
+    return {
+        type: 'Hash',
+        loc: this.getLocation(start, this.tokenStart),
+        value: this.substrToCursor(start + 1)
+    };
+}
+export function generate(node) {
+    this.token(Hash, '#' + node.value);
+}
+

node_modules/css-tree/lib/syntax/node/IdSelector.js

@@ -0,0 +1,26 @@
+import { Hash, Delim } from '../../tokenizer/index.js';
+
+export const name = 'IdSelector';
+export const structure = {
+    name: String
+};
+
+export function parse() {
+    const start = this.tokenStart;
+
+    // TODO: check value is an ident
+    this.eat(Hash);
+
+    return {
+        type: 'IdSelector',
+        loc: this.getLocation(start, this.tokenStart),
+        name: this.substrToCursor(start + 1)
+    };
+}
+
+export function generate(node) {
+    // Using Delim instead of Hash is a hack to avoid for a whitespace between ident and id-selector
+    // in safe mode (e.g. "a#id"), because IE11 doesn't allow a sequence <ident-token> <hash-token>
+    // without a whitespace in values (e.g. "1px solid#000")
+    this.token(Delim, '#' + node.name);
+}

node_modules/css-tree/lib/syntax/node/Identifier.js

@@ -0,0 +1,18 @@
+import { Ident } from '../../tokenizer/index.js';
+
+export const name = 'Identifier';
+export const structure = {
+    name: String
+};
+
+export function parse() {
+    return {
+        type: 'Identifier',
+        loc: this.getLocation(this.tokenStart, this.tokenEnd),
+        name: this.consume(Ident)
+    };
+}
+
+export function generate(node) {
+    this.token(Ident, node.name);
+}

node_modules/css-tree/lib/syntax/node/MediaFeature.js

@@ -0,0 +1,77 @@
+import {
+    Ident,
+    Number,
+    Dimension,
+    LeftParenthesis,
+    RightParenthesis,
+    Colon,
+    Delim
+} from '../../tokenizer/index.js';
+
+export const name = 'MediaFeature';
+export const structure = {
+    name: String,
+    value: ['Identifier', 'Number', 'Dimension', 'Ratio', null]
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    let name;
+    let value = null;
+
+    this.eat(LeftParenthesis);
+    this.skipSC();
+
+    name = this.consume(Ident);
+    this.skipSC();
+
+    if (this.tokenType !== RightParenthesis) {
+        this.eat(Colon);
+        this.skipSC();
+
+        switch (this.tokenType) {
+            case Number:
+                if (this.lookupNonWSType(1) === Delim) {
+                    value = this.Ratio();
+                } else {
+                    value = this.Number();
+                }
+
+                break;
+
+            case Dimension:
+                value = this.Dimension();
+                break;
+
+            case Ident:
+                value = this.Identifier();
+                break;
+
+            default:
+                this.error('Number, dimension, ratio or identifier is expected');
+        }
+
+        this.skipSC();
+    }
+
+    this.eat(RightParenthesis);
+
+    return {
+        type: 'MediaFeature',
+        loc: this.getLocation(start, this.tokenStart),
+        name,
+        value
+    };
+}
+
+export function generate(node) {
+    this.token(LeftParenthesis, '(');
+    this.token(Ident, node.name);
+
+    if (node.value !== null) {
+        this.token(Colon, ':');
+        this.node(node.value);
+    }
+
+    this.token(RightParenthesis, ')');
+}

node_modules/css-tree/lib/syntax/node/MediaQuery.js

@@ -0,0 +1,60 @@
+import {
+    WhiteSpace,
+    Comment,
+    Ident,
+    LeftParenthesis
+} from '../../tokenizer/index.js';
+
+export const name = 'MediaQuery';
+export const structure = {
+    children: [[
+        'Identifier',
+        'MediaFeature',
+        'WhiteSpace'
+    ]]
+};
+
+export function parse() {
+    const children = this.createList();
+    let child = null;
+
+    this.skipSC();
+
+    scan:
+    while (!this.eof) {
+        switch (this.tokenType) {
+            case Comment:
+            case WhiteSpace:
+                this.next();
+                continue;
+
+            case Ident:
+                child = this.Identifier();
+                break;
+
+            case LeftParenthesis:
+                child = this.MediaFeature();
+                break;
+
+            default:
+                break scan;
+        }
+
+        children.push(child);
+    }
+
+    if (child === null) {
+        this.error('Identifier or parenthesis is expected');
+    }
+
+    return {
+        type: 'MediaQuery',
+        loc: this.getLocationFromList(children),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node);
+}
+

node_modules/css-tree/lib/syntax/node/MediaQueryList.js

@@ -0,0 +1,34 @@
+import { Comma } from '../../tokenizer/index.js';
+
+export const name = 'MediaQueryList';
+export const structure = {
+    children: [[
+        'MediaQuery'
+    ]]
+};
+
+export function parse() {
+    const children = this.createList();
+
+    this.skipSC();
+
+    while (!this.eof) {
+        children.push(this.MediaQuery());
+
+        if (this.tokenType !== Comma) {
+            break;
+        }
+
+        this.next();
+    }
+
+    return {
+        type: 'MediaQueryList',
+        loc: this.getLocationFromList(children),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node, () => this.token(Comma, ','));
+}

node_modules/css-tree/lib/syntax/node/Nth.js

@@ -0,0 +1,47 @@
+import { Ident } from '../../tokenizer/index.js';
+
+export const name = 'Nth';
+export const structure = {
+    nth: ['AnPlusB', 'Identifier'],
+    selector: ['SelectorList', null]
+};
+
+export function parse() {
+    this.skipSC();
+
+    const start = this.tokenStart;
+    let end = start;
+    let selector = null;
+    let nth;
+
+    if (this.lookupValue(0, 'odd') || this.lookupValue(0, 'even')) {
+        nth = this.Identifier();
+    } else {
+        nth = this.AnPlusB();
+    }
+
+    end = this.tokenStart;
+    this.skipSC();
+
+    if (this.lookupValue(0, 'of')) {
+        this.next();
+
+        selector = this.SelectorList();
+        end = this.tokenStart;
+    }
+
+    return {
+        type: 'Nth',
+        loc: this.getLocation(start, end),
+        nth,
+        selector
+    };
+}
+
+export function generate(node) {
+    this.node(node.nth);
+    if (node.selector !== null) {
+        this.token(Ident, 'of');
+        this.node(node.selector);
+    }
+}

node_modules/css-tree/lib/syntax/node/Number.js

@@ -0,0 +1,18 @@
+import { Number as NumberToken } from '../../tokenizer/index.js';
+
+export const name = 'Number';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    return {
+        type: 'Number',
+        loc: this.getLocation(this.tokenStart, this.tokenEnd),
+        value: this.consume(NumberToken)
+    };
+}
+
+export function generate(node) {
+    this.token(NumberToken, node.value);
+}

node_modules/css-tree/lib/syntax/node/Operator.js

@@ -0,0 +1,21 @@
+// '/' | '*' | ',' | ':' | '+' | '-'
+export const name = 'Operator';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    const start = this.tokenStart;
+
+    this.next();
+
+    return {
+        type: 'Operator',
+        loc: this.getLocation(start, this.tokenStart),
+        value: this.substrToCursor(start)
+    };
+}
+
+export function generate(node) {
+    this.tokenize(node.value);
+}

node_modules/css-tree/lib/syntax/node/Parentheses.js

@@ -0,0 +1,34 @@
+import {
+    LeftParenthesis,
+    RightParenthesis
+} from '../../tokenizer/index.js';
+
+export const name = 'Parentheses';
+export const structure = {
+    children: [[]]
+};
+
+export function parse(readSequence, recognizer) {
+    const start = this.tokenStart;
+    let children = null;
+
+    this.eat(LeftParenthesis);
+
+    children = readSequence.call(this, recognizer);
+
+    if (!this.eof) {
+        this.eat(RightParenthesis);
+    }
+
+    return {
+        type: 'Parentheses',
+        loc: this.getLocation(start, this.tokenStart),
+        children
+    };
+}
+
+export function generate(node) {
+    this.token(LeftParenthesis, '(');
+    this.children(node);
+    this.token(RightParenthesis, ')');
+}

node_modules/css-tree/lib/syntax/node/Percentage.js

@@ -0,0 +1,18 @@
+import { Percentage } from '../../tokenizer/index.js';
+
+export const name = 'Percentage';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    return {
+        type: 'Percentage',
+        loc: this.getLocation(this.tokenStart, this.tokenEnd),
+        value: this.consumeNumber(Percentage)
+    };
+}
+
+export function generate(node) {
+    this.token(Percentage, node.value + '%');
+}

node_modules/css-tree/lib/syntax/node/PseudoClassSelector.js

@@ -0,0 +1,63 @@
+import {
+    Ident,
+    Function as FunctionToken,
+    Colon,
+    RightParenthesis
+} from '../../tokenizer/index.js';
+
+
+export const name = 'PseudoClassSelector';
+export const walkContext = 'function';
+export const structure = {
+    name: String,
+    children: [['Raw'], null]
+};
+
+// : [ <ident> | <function-token> <any-value>? ) ]
+export function parse() {
+    const start = this.tokenStart;
+    let children = null;
+    let name;
+    let nameLowerCase;
+
+    this.eat(Colon);
+
+    if (this.tokenType === FunctionToken) {
+        name = this.consumeFunctionName();
+        nameLowerCase = name.toLowerCase();
+
+        if (hasOwnProperty.call(this.pseudo, nameLowerCase)) {
+            this.skipSC();
+            children = this.pseudo[nameLowerCase].call(this);
+            this.skipSC();
+        } else {
+            children = this.createList();
+            children.push(
+                this.Raw(this.tokenIndex, null, false)
+            );
+        }
+
+        this.eat(RightParenthesis);
+    } else {
+        name = this.consume(Ident);
+    }
+
+    return {
+        type: 'PseudoClassSelector',
+        loc: this.getLocation(start, this.tokenStart),
+        name,
+        children
+    };
+}
+
+export function generate(node) {
+    this.token(Colon, ':');
+
+    if (node.children === null) {
+        this.token(Ident, node.name);
+    } else {
+        this.token(FunctionToken, node.name + '(');
+        this.children(node);
+        this.token(RightParenthesis, ')');
+    }
+}

node_modules/css-tree/lib/syntax/node/PseudoElementSelector.js

@@ -0,0 +1,64 @@
+import {
+    Ident,
+    Function as FunctionToken,
+    Colon,
+    RightParenthesis
+} from '../../tokenizer/index.js';
+
+export const name = 'PseudoElementSelector';
+export const walkContext = 'function';
+export const structure = {
+    name: String,
+    children: [['Raw'], null]
+};
+
+// :: [ <ident> | <function-token> <any-value>? ) ]
+export function parse() {
+    const start = this.tokenStart;
+    let children = null;
+    let name;
+    let nameLowerCase;
+
+    this.eat(Colon);
+    this.eat(Colon);
+
+    if (this.tokenType === FunctionToken) {
+        name = this.consumeFunctionName();
+        nameLowerCase = name.toLowerCase();
+
+        if (hasOwnProperty.call(this.pseudo, nameLowerCase)) {
+            this.skipSC();
+            children = this.pseudo[nameLowerCase].call(this);
+            this.skipSC();
+        } else {
+            children = this.createList();
+            children.push(
+                this.Raw(this.tokenIndex, null, false)
+            );
+        }
+
+        this.eat(RightParenthesis);
+    } else {
+        name = this.consume(Ident);
+    }
+
+    return {
+        type: 'PseudoElementSelector',
+        loc: this.getLocation(start, this.tokenStart),
+        name,
+        children
+    };
+}
+
+export function generate(node) {
+    this.token(Colon, ':');
+    this.token(Colon, ':');
+
+    if (node.children === null) {
+        this.token(Ident, node.name);
+    } else {
+        this.token(FunctionToken, node.name + '(');
+        this.children(node);
+        this.token(RightParenthesis, ')');
+    }
+}

node_modules/css-tree/lib/syntax/node/Ratio.js

@@ -0,0 +1,59 @@
+import { isDigit, Delim, Number as NumberToken } from '../../tokenizer/index.js';
+
+const SOLIDUS = 0x002F;  // U+002F SOLIDUS (/)
+const FULLSTOP = 0x002E; // U+002E FULL STOP (.)
+
+// Terms of <ratio> should be a positive numbers (not zero or negative)
+// (see https://drafts.csswg.org/mediaqueries-3/#values)
+// However, -o-min-device-pixel-ratio takes fractional values as a ratio's term
+// and this is using by various sites. Therefore we relax checking on parse
+// to test a term is unsigned number without an exponent part.
+// Additional checking may be applied on lexer validation.
+function consumeNumber() {
+    this.skipSC();
+
+    const value = this.consume(NumberToken);
+
+    for (let i = 0; i < value.length; i++) {
+        const code = value.charCodeAt(i);
+        if (!isDigit(code) && code !== FULLSTOP) {
+            this.error('Unsigned number is expected', this.tokenStart - value.length + i);
+        }
+    }
+
+    if (Number(value) === 0) {
+        this.error('Zero number is not allowed', this.tokenStart - value.length);
+    }
+
+    return value;
+}
+
+export const name = 'Ratio';
+export const structure = {
+    left: String,
+    right: String
+};
+
+// <positive-integer> S* '/' S* <positive-integer>
+export function parse() {
+    const start = this.tokenStart;
+    const left = consumeNumber.call(this);
+    let right;
+
+    this.skipSC();
+    this.eatDelim(SOLIDUS);
+    right = consumeNumber.call(this);
+
+    return {
+        type: 'Ratio',
+        loc: this.getLocation(start, this.tokenStart),
+        left,
+        right
+    };
+}
+
+export function generate(node) {
+    this.token(NumberToken, node.left);
+    this.token(Delim, '/');
+    this.token(NumberToken, node.right);
+}

node_modules/css-tree/lib/syntax/node/Raw.js

@@ -0,0 +1,41 @@
+import { WhiteSpace } from '../../tokenizer/index.js';
+
+function getOffsetExcludeWS() {
+    if (this.tokenIndex > 0) {
+        if (this.lookupType(-1) === WhiteSpace) {
+            return this.tokenIndex > 1
+                ? this.getTokenStart(this.tokenIndex - 1)
+                : this.firstCharOffset;
+        }
+    }
+
+    return this.tokenStart;
+}
+
+export const name = 'Raw';
+export const structure = {
+    value: String
+};
+
+export function parse(startToken, consumeUntil, excludeWhiteSpace) {
+    const startOffset = this.getTokenStart(startToken);
+    let endOffset;
+
+    this.skipUntilBalanced(startToken, consumeUntil || this.consumeUntilBalanceEnd);
+
+    if (excludeWhiteSpace && this.tokenStart > startOffset) {
+        endOffset = getOffsetExcludeWS.call(this);
+    } else {
+        endOffset = this.tokenStart;
+    }
+
+    return {
+        type: 'Raw',
+        loc: this.getLocation(startOffset, endOffset),
+        value: this.substring(startOffset, endOffset)
+    };
+}
+
+export function generate(node) {
+    this.tokenize(node.value);
+}

node_modules/css-tree/lib/syntax/node/Rule.js

@@ -0,0 +1,51 @@
+import { LeftCurlyBracket } from '../../tokenizer/index.js';
+
+function consumeRaw(startToken) {
+    return this.Raw(startToken, this.consumeUntilLeftCurlyBracket, true);
+}
+
+function consumePrelude() {
+    const prelude = this.SelectorList();
+
+    if (prelude.type !== 'Raw' &&
+        this.eof === false &&
+        this.tokenType !== LeftCurlyBracket) {
+        this.error();
+    }
+
+    return prelude;
+}
+
+export const name = 'Rule';
+export const walkContext = 'rule';
+export const structure = {
+    prelude: ['SelectorList', 'Raw'],
+    block: ['Block']
+};
+
+export function parse() {
+    const startToken = this.tokenIndex;
+    const startOffset = this.tokenStart;
+    let prelude;
+    let block;
+
+    if (this.parseRulePrelude) {
+        prelude = this.parseWithFallback(consumePrelude, consumeRaw);
+    } else {
+        prelude = consumeRaw.call(this, startToken);
+    }
+
+    block = this.Block(true);
+
+    return {
+        type: 'Rule',
+        loc: this.getLocation(startOffset, this.tokenStart),
+        prelude,
+        block
+    };
+}
+export function generate(node) {
+    this.node(node.prelude);
+    this.node(node.block);
+}
+

node_modules/css-tree/lib/syntax/node/Selector.js

@@ -0,0 +1,32 @@
+export const name = 'Selector';
+export const structure = {
+    children: [[
+        'TypeSelector',
+        'IdSelector',
+        'ClassSelector',
+        'AttributeSelector',
+        'PseudoClassSelector',
+        'PseudoElementSelector',
+        'Combinator',
+        'WhiteSpace'
+    ]]
+};
+
+export function parse() {
+    const children = this.readSequence(this.scope.Selector);
+
+    // nothing were consumed
+    if (this.getFirstListNode(children) === null) {
+        this.error('Selector is expected');
+    }
+
+    return {
+        type: 'Selector',
+        loc: this.getLocationFromList(children),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node);
+}

node_modules/css-tree/lib/syntax/node/SelectorList.js

@@ -0,0 +1,35 @@
+import { Comma } from '../../tokenizer/index.js';
+
+export const name = 'SelectorList';
+export const walkContext = 'selector';
+export const structure = {
+    children: [[
+        'Selector',
+        'Raw'
+    ]]
+};
+
+export function parse() {
+    const children = this.createList();
+
+    while (!this.eof) {
+        children.push(this.Selector());
+
+        if (this.tokenType === Comma) {
+            this.next();
+            continue;
+        }
+
+        break;
+    }
+
+    return {
+        type: 'SelectorList',
+        loc: this.getLocationFromList(children),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node, () => this.token(Comma, ','));
+}

node_modules/css-tree/lib/syntax/node/String.js

@@ -0,0 +1,19 @@
+import { String as StringToken } from '../../tokenizer/index.js';
+import { decode, encode } from '../../utils/string.js';
+
+export const name = 'String';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    return {
+        type: 'String',
+        loc: this.getLocation(this.tokenStart, this.tokenEnd),
+        value: decode(this.consume(StringToken))
+    };
+}
+
+export function generate(node) {
+    this.token(StringToken, encode(node.value));
+}

node_modules/css-tree/lib/syntax/node/StyleSheet.js

@@ -0,0 +1,82 @@
+import {
+    WhiteSpace,
+    Comment,
+    AtKeyword,
+    CDO,
+    CDC
+} from '../../tokenizer/index.js';
+
+const EXCLAMATIONMARK = 0x0021; // U+0021 EXCLAMATION MARK (!)
+
+function consumeRaw(startToken) {
+    return this.Raw(startToken, null, false);
+}
+
+export const name = 'StyleSheet';
+export const walkContext = 'stylesheet';
+export const structure = {
+    children: [[
+        'Comment',
+        'CDO',
+        'CDC',
+        'Atrule',
+        'Rule',
+        'Raw'
+    ]]
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    const children = this.createList();
+    let child;
+
+    scan:
+    while (!this.eof) {
+        switch (this.tokenType) {
+            case WhiteSpace:
+                this.next();
+                continue;
+
+            case Comment:
+                // ignore comments except exclamation comments (i.e. /*! .. */) on top level
+                if (this.charCodeAt(this.tokenStart + 2) !== EXCLAMATIONMARK) {
+                    this.next();
+                    continue;
+                }
+
+                child = this.Comment();
+                break;
+
+            case CDO: // <!--
+                child = this.CDO();
+                break;
+
+            case CDC: // -->
+                child = this.CDC();
+                break;
+
+            // CSS Syntax Module Level 3
+            // §2.2 Error handling
+            // At the "top level" of a stylesheet, an <at-keyword-token> starts an at-rule.
+            case AtKeyword:
+                child = this.parseWithFallback(this.Atrule, consumeRaw);
+                break;
+
+            // Anything else starts a qualified rule ...
+            default:
+                child = this.parseWithFallback(this.Rule, consumeRaw);
+        }
+
+        children.push(child);
+    }
+
+    return {
+        type: 'StyleSheet',
+        loc: this.getLocation(start, this.tokenStart),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node);
+}

node_modules/css-tree/lib/syntax/node/TypeSelector.js

@@ -0,0 +1,52 @@
+import { Ident } from '../../tokenizer/index.js';
+
+const ASTERISK = 0x002A;     // U+002A ASTERISK (*)
+const VERTICALLINE = 0x007C; // U+007C VERTICAL LINE (|)
+
+function eatIdentifierOrAsterisk() {
+    if (this.tokenType !== Ident &&
+        this.isDelim(ASTERISK) === false) {
+        this.error('Identifier or asterisk is expected');
+    }
+
+    this.next();
+}
+
+export const name = 'TypeSelector';
+export const structure = {
+    name: String
+};
+
+// ident
+// ident|ident
+// ident|*
+// *
+// *|ident
+// *|*
+// |ident
+// |*
+export function parse() {
+    const start = this.tokenStart;
+
+    if (this.isDelim(VERTICALLINE)) {
+        this.next();
+        eatIdentifierOrAsterisk.call(this);
+    } else {
+        eatIdentifierOrAsterisk.call(this);
+
+        if (this.isDelim(VERTICALLINE)) {
+            this.next();
+            eatIdentifierOrAsterisk.call(this);
+        }
+    }
+
+    return {
+        type: 'TypeSelector',
+        loc: this.getLocation(start, this.tokenStart),
+        name: this.substrToCursor(start)
+    };
+}
+
+export function generate(node) {
+    this.tokenize(node.name);
+}

node_modules/css-tree/lib/syntax/node/UnicodeRange.js

@@ -0,0 +1,156 @@
+import {
+    isHexDigit,
+    Ident,
+    Number,
+    Dimension
+} from '../../tokenizer/index.js';
+
+const PLUSSIGN = 0x002B;     // U+002B PLUS SIGN (+)
+const HYPHENMINUS = 0x002D;  // U+002D HYPHEN-MINUS (-)
+const QUESTIONMARK = 0x003F; // U+003F QUESTION MARK (?)
+
+function eatHexSequence(offset, allowDash) {
+    let len = 0;
+
+    for (let pos = this.tokenStart + offset; pos < this.tokenEnd; pos++) {
+        const code = this.charCodeAt(pos);
+
+        if (code === HYPHENMINUS && allowDash && len !== 0) {
+            eatHexSequence.call(this, offset + len + 1, false);
+            return -1;
+        }
+
+        if (!isHexDigit(code)) {
+            this.error(
+                allowDash && len !== 0
+                    ? 'Hyphen minus' + (len < 6 ? ' or hex digit' : '') + ' is expected'
+                    : (len < 6 ? 'Hex digit is expected' : 'Unexpected input'),
+                pos
+            );
+        }
+
+        if (++len > 6) {
+            this.error('Too many hex digits', pos);
+        };
+    }
+
+    this.next();
+    return len;
+}
+
+function eatQuestionMarkSequence(max) {
+    let count = 0;
+
+    while (this.isDelim(QUESTIONMARK)) {
+        if (++count > max) {
+            this.error('Too many question marks');
+        }
+
+        this.next();
+    }
+}
+
+function startsWith(code) {
+    if (this.charCodeAt(this.tokenStart) !== code) {
+        this.error((code === PLUSSIGN ? 'Plus sign' : 'Hyphen minus') + ' is expected');
+    }
+}
+
+// https://drafts.csswg.org/css-syntax/#urange
+// Informally, the <urange> production has three forms:
+// U+0001
+//      Defines a range consisting of a single code point, in this case the code point "1".
+// U+0001-00ff
+//      Defines a range of codepoints between the first and the second value, in this case
+//      the range between "1" and "ff" (255 in decimal) inclusive.
+// U+00??
+//      Defines a range of codepoints where the "?" characters range over all hex digits,
+//      in this case defining the same as the value U+0000-00ff.
+// In each form, a maximum of 6 digits is allowed for each hexadecimal number (if you treat "?" as a hexadecimal digit).
+//
+// <urange> =
+//   u '+' <ident-token> '?'* |
+//   u <dimension-token> '?'* |
+//   u <number-token> '?'* |
+//   u <number-token> <dimension-token> |
+//   u <number-token> <number-token> |
+//   u '+' '?'+
+function scanUnicodeRange() {
+    let hexLength = 0;
+
+    switch (this.tokenType) {
+        case Number:
+            // u <number-token> '?'*
+            // u <number-token> <dimension-token>
+            // u <number-token> <number-token>
+            hexLength = eatHexSequence.call(this, 1, true);
+
+            if (this.isDelim(QUESTIONMARK)) {
+                eatQuestionMarkSequence.call(this, 6 - hexLength);
+                break;
+            }
+
+            if (this.tokenType === Dimension ||
+                this.tokenType === Number) {
+                startsWith.call(this, HYPHENMINUS);
+                eatHexSequence.call(this, 1, false);
+                break;
+            }
+
+            break;
+
+        case Dimension:
+            // u <dimension-token> '?'*
+            hexLength = eatHexSequence.call(this, 1, true);
+
+            if (hexLength > 0) {
+                eatQuestionMarkSequence.call(this, 6 - hexLength);
+            }
+
+            break;
+
+        default:
+            // u '+' <ident-token> '?'*
+            // u '+' '?'+
+            this.eatDelim(PLUSSIGN);
+
+            if (this.tokenType === Ident) {
+                hexLength = eatHexSequence.call(this, 0, true);
+                if (hexLength > 0) {
+                    eatQuestionMarkSequence.call(this, 6 - hexLength);
+                }
+                break;
+            }
+
+            if (this.isDelim(QUESTIONMARK)) {
+                this.next();
+                eatQuestionMarkSequence.call(this, 5);
+                break;
+            }
+
+            this.error('Hex digit or question mark is expected');
+    }
+}
+
+export const name = 'UnicodeRange';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    const start = this.tokenStart;
+
+    // U or u
+    this.eatIdent('u');
+    scanUnicodeRange.call(this);
+
+    return {
+        type: 'UnicodeRange',
+        loc: this.getLocation(start, this.tokenStart),
+        value: this.substrToCursor(start)
+    };
+}
+
+export function generate(node) {
+    this.tokenize(node.value);
+}

node_modules/css-tree/lib/syntax/node/Url.js

@@ -0,0 +1,52 @@
+import * as url from '../../utils/url.js';
+import * as string from '../../utils/string.js';
+import {
+    Function as FunctionToken,
+    String as StringToken,
+    Url,
+    RightParenthesis
+} from '../../tokenizer/index.js';
+
+export const name = 'Url';
+export const structure = {
+    value: String
+};
+
+// <url-token> | <function-token> <string> )
+export function parse() {
+    const start = this.tokenStart;
+    let value;
+
+    switch (this.tokenType) {
+        case Url:
+            value = url.decode(this.consume(Url));
+            break;
+
+        case FunctionToken:
+            if (!this.cmpStr(this.tokenStart, this.tokenEnd, 'url(')) {
+                this.error('Function name must be `url`');
+            }
+
+            this.eat(FunctionToken);
+            this.skipSC();
+            value = string.decode(this.consume(StringToken));
+            this.skipSC();
+            if (!this.eof) {
+                this.eat(RightParenthesis);
+            }
+            break;
+
+        default:
+            this.error('Url or Function is expected');
+    }
+
+    return {
+        type: 'Url',
+        loc: this.getLocation(start, this.tokenStart),
+        value
+    };
+}
+
+export function generate(node) {
+    this.token(Url, url.encode(node.value));
+}

node_modules/css-tree/lib/syntax/node/Value.js

@@ -0,0 +1,19 @@
+export const name = 'Value';
+export const structure = {
+    children: [[]]
+};
+
+export function parse() {
+    const start = this.tokenStart;
+    const children = this.readSequence(this.scope.Value);
+
+    return {
+        type: 'Value',
+        loc: this.getLocation(start, this.tokenStart),
+        children
+    };
+}
+
+export function generate(node) {
+    this.children(node);
+}

node_modules/css-tree/lib/syntax/node/WhiteSpace.js

@@ -0,0 +1,27 @@
+import { WhiteSpace } from '../../tokenizer/index.js';
+
+const SPACE = Object.freeze({
+    type: 'WhiteSpace',
+    loc: null,
+    value: ' '
+});
+
+export const name = 'WhiteSpace';
+export const structure = {
+    value: String
+};
+
+export function parse() {
+    this.eat(WhiteSpace);
+    return SPACE;
+
+    // return {
+    //     type: 'WhiteSpace',
+    //     loc: this.getLocation(this.tokenStart, this.tokenEnd),
+    //     value: this.consume(WHITESPACE)
+    // };
+}
+
+export function generate(node) {
+    this.token(WhiteSpace, node.value);
+}

node_modules/css-tree/lib/syntax/node/index-generate.js

@@ -0,0 +1,40 @@
+export { generate as AnPlusB } from './AnPlusB.js';
+export { generate as Atrule } from './Atrule.js';
+export { generate as AtrulePrelude } from './AtrulePrelude.js';
+export { generate as AttributeSelector } from './AttributeSelector.js';
+export { generate as Block } from './Block.js';
+export { generate as Brackets } from './Brackets.js';
+export { generate as CDC } from './CDC.js';
+export { generate as CDO } from './CDO.js';
+export { generate as ClassSelector } from './ClassSelector.js';
+export { generate as Combinator } from './Combinator.js';
+export { generate as Comment } from './Comment.js';
+export { generate as Declaration } from './Declaration.js';
+export { generate as DeclarationList } from './DeclarationList.js';
+export { generate as Dimension } from './Dimension.js';
+export { generate as Function } from './Function.js';
+export { generate as Hash } from './Hash.js';
+export { generate as Identifier } from './Identifier.js';
+export { generate as IdSelector } from './IdSelector.js';
+export { generate as MediaFeature } from './MediaFeature.js';
+export { generate as MediaQuery } from './MediaQuery.js';
+export { generate as MediaQueryList } from './MediaQueryList.js';
+export { generate as Nth } from './Nth.js';
+export { generate as Number } from './Number.js';
+export { generate as Operator } from './Operator.js';
+export { generate as Parentheses } from './Parentheses.js';
+export { generate as Percentage } from './Percentage.js';
+export { generate as PseudoClassSelector } from './PseudoClassSelector.js';
+export { generate as PseudoElementSelector } from './PseudoElementSelector.js';
+export { generate as Ratio } from './Ratio.js';
+export { generate as Raw } from './Raw.js';
+export { generate as Rule } from './Rule.js';
+export { generate as Selector } from './Selector.js';
+export { generate as SelectorList } from './SelectorList.js';
+export { generate as String } from './String.js';
+export { generate as StyleSheet } from './StyleSheet.js';
+export { generate as TypeSelector } from './TypeSelector.js';
+export { generate as UnicodeRange } from './UnicodeRange.js';
+export { generate as Url } from './Url.js';
+export { generate as Value } from './Value.js';
+export { generate as WhiteSpace } from './WhiteSpace.js';

node_modules/css-tree/lib/syntax/node/index-parse-selector.js

@@ -0,0 +1,15 @@
+export { parse as AnPlusB } from './AnPlusB.js';
+export { parse as AttributeSelector } from './AttributeSelector.js';
+export { parse as ClassSelector } from './ClassSelector.js';
+export { parse as Combinator } from './Combinator.js';
+export { parse as Identifier } from './Identifier.js';
+export { parse as IdSelector } from './IdSelector.js';
+export { parse as Nth } from './Nth.js';
+export { parse as Percentage } from './Percentage.js';
+export { parse as PseudoClassSelector } from './PseudoClassSelector.js';
+export { parse as PseudoElementSelector } from './PseudoElementSelector.js';
+export { parse as Raw } from './Raw.js';
+export { parse as Selector } from './Selector.js';
+export { parse as SelectorList } from './SelectorList.js';
+export { parse as String } from './String.js';
+export { parse as TypeSelector } from './TypeSelector.js';

node_modules/css-tree/lib/syntax/node/index-parse.js

@@ -0,0 +1,40 @@
+export { parse as AnPlusB } from './AnPlusB.js';
+export { parse as Atrule } from './Atrule.js';
+export { parse as AtrulePrelude } from './AtrulePrelude.js';
+export { parse as AttributeSelector } from './AttributeSelector.js';
+export { parse as Block } from './Block.js';
+export { parse as Brackets } from './Brackets.js';
+export { parse as CDC } from './CDC.js';
+export { parse as CDO } from './CDO.js';
+export { parse as ClassSelector } from './ClassSelector.js';
+export { parse as Combinator } from './Combinator.js';
+export { parse as Comment } from './Comment.js';
+export { parse as Declaration } from './Declaration.js';
+export { parse as DeclarationList } from './DeclarationList.js';
+export { parse as Dimension } from './Dimension.js';
+export { parse as Function } from './Function.js';
+export { parse as Hash } from './Hash.js';
+export { parse as Identifier } from './Identifier.js';
+export { parse as IdSelector } from './IdSelector.js';
+export { parse as MediaFeature } from './MediaFeature.js';
+export { parse as MediaQuery } from './MediaQuery.js';
+export { parse as MediaQueryList } from './MediaQueryList.js';
+export { parse as Nth } from './Nth.js';
+export { parse as Number } from './Number.js';
+export { parse as Operator } from './Operator.js';
+export { parse as Parentheses } from './Parentheses.js';
+export { parse as Percentage } from './Percentage.js';
+export { parse as PseudoClassSelector } from './PseudoClassSelector.js';
+export { parse as PseudoElementSelector } from './PseudoElementSelector.js';
+export { parse as Ratio } from './Ratio.js';
+export { parse as Raw } from './Raw.js';
+export { parse as Rule } from './Rule.js';
+export { parse as Selector } from './Selector.js';
+export { parse as SelectorList } from './SelectorList.js';
+export { parse as String } from './String.js';
+export { parse as StyleSheet } from './StyleSheet.js';
+export { parse as TypeSelector } from './TypeSelector.js';
+export { parse as UnicodeRange } from './UnicodeRange.js';
+export { parse as Url } from './Url.js';
+export { parse as Value } from './Value.js';
+export { parse as WhiteSpace } from './WhiteSpace.js';

node_modules/css-tree/lib/syntax/node/index.js

@@ -0,0 +1,40 @@
+export * as AnPlusB from './AnPlusB.js';
+export * as Atrule from './Atrule.js';
+export * as AtrulePrelude from './AtrulePrelude.js';
+export * as AttributeSelector from './AttributeSelector.js';
+export * as Block from './Block.js';
+export * as Brackets from './Brackets.js';
+export * as CDC from './CDC.js';
+export * as CDO from './CDO.js';
+export * as ClassSelector from './ClassSelector.js';
+export * as Combinator from './Combinator.js';
+export * as Comment from './Comment.js';
+export * as Declaration from './Declaration.js';
+export * as DeclarationList from './DeclarationList.js';
+export * as Dimension from './Dimension.js';
+export * as Function from './Function.js';
+export * as Hash from './Hash.js';
+export * as Identifier from './Identifier.js';
+export * as IdSelector from './IdSelector.js';
+export * as MediaFeature from './MediaFeature.js';
+export * as MediaQuery from './MediaQuery.js';
+export * as MediaQueryList from './MediaQueryList.js';
+export * as Nth from './Nth.js';
+export * as Number from './Number.js';
+export * as Operator from './Operator.js';
+export * as Parentheses from './Parentheses.js';
+export * as Percentage from './Percentage.js';
+export * as PseudoClassSelector from './PseudoClassSelector.js';
+export * as PseudoElementSelector from './PseudoElementSelector.js';
+export * as Ratio from './Ratio.js';
+export * as Raw from './Raw.js';
+export * as Rule from './Rule.js';
+export * as Selector from './Selector.js';
+export * as SelectorList from './SelectorList.js';
+export * as String from './String.js';
+export * as StyleSheet from './StyleSheet.js';
+export * as TypeSelector from './TypeSelector.js';
+export * as UnicodeRange from './UnicodeRange.js';
+export * as Url from './Url.js';
+export * as Value from './Value.js';
+export * as WhiteSpace from './WhiteSpace.js';

node_modules/css-tree/lib/syntax/pseudo/index.js

@@ -0,0 +1,48 @@
+const selectorList = {
+    parse() {
+        return this.createSingleNodeList(
+            this.SelectorList()
+        );
+    }
+};
+
+const selector = {
+    parse() {
+        return this.createSingleNodeList(
+            this.Selector()
+        );
+    }
+};
+
+const identList = {
+    parse() {
+        return this.createSingleNodeList(
+            this.Identifier()
+        );
+    }
+};
+
+const nth = {
+    parse() {
+        return this.createSingleNodeList(
+            this.Nth()
+        );
+    }
+};
+
+export default {
+    'dir': identList,
+    'has': selectorList,
+    'lang': identList,
+    'matches': selectorList,
+    'is': selectorList,
+    '-moz-any': selectorList,
+    '-webkit-any': selectorList,
+    'where': selectorList,
+    'not': selectorList,
+    'nth-child': nth,
+    'nth-last-child': nth,
+    'nth-last-of-type': nth,
+    'nth-of-type': nth,
+    'slotted': selector
+};

node_modules/css-tree/lib/syntax/scope/atrulePrelude.js

@@ -0,0 +1,5 @@
+import getNode from './default.js';
+
+export default {
+    getNode
+};

node_modules/css-tree/lib/syntax/scope/default.js

@@ -0,0 +1,85 @@
+import {
+    Ident,
+    String as StringToken,
+    Number as NumberToken,
+    Function as FunctionToken,
+    Url,
+    Hash,
+    Dimension,
+    Percentage,
+    LeftParenthesis,
+    LeftSquareBracket,
+    Comma,
+    Delim
+} from '../../tokenizer/index.js';
+
+const NUMBERSIGN = 0x0023;  // U+0023 NUMBER SIGN (#)
+const ASTERISK = 0x002A;    // U+002A ASTERISK (*)
+const PLUSSIGN = 0x002B;    // U+002B PLUS SIGN (+)
+const HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
+const SOLIDUS = 0x002F;     // U+002F SOLIDUS (/)
+const U = 0x0075;           // U+0075 LATIN SMALL LETTER U (u)
+
+export default function defaultRecognizer(context) {
+    switch (this.tokenType) {
+        case Hash:
+            return this.Hash();
+
+        case Comma:
+            return this.Operator();
+
+        case LeftParenthesis:
+            return this.Parentheses(this.readSequence, context.recognizer);
+
+        case LeftSquareBracket:
+            return this.Brackets(this.readSequence, context.recognizer);
+
+        case StringToken:
+            return this.String();
+
+        case Dimension:
+            return this.Dimension();
+
+        case Percentage:
+            return this.Percentage();
+
+        case NumberToken:
+            return this.Number();
+
+        case FunctionToken:
+            return this.cmpStr(this.tokenStart, this.tokenEnd, 'url(')
+                ? this.Url()
+                : this.Function(this.readSequence, context.recognizer);
+
+        case Url:
+            return this.Url();
+
+        case Ident:
+            // check for unicode range, it should start with u+ or U+
+            if (this.cmpChar(this.tokenStart, U) &&
+                this.cmpChar(this.tokenStart + 1, PLUSSIGN)) {
+                return this.UnicodeRange();
+            } else {
+                return this.Identifier();
+            }
+
+        case Delim: {
+            const code = this.charCodeAt(this.tokenStart);
+
+            if (code === SOLIDUS ||
+                code === ASTERISK ||
+                code === PLUSSIGN ||
+                code === HYPHENMINUS) {
+                return this.Operator(); // TODO: replace with Delim
+            }
+
+            // TODO: produce a node with Delim node type
+
+            if (code === NUMBERSIGN) {
+                this.error('Hex or identifier is expected', this.tokenStart + 1);
+            }
+
+            break;
+        }
+    }
+};

node_modules/css-tree/lib/syntax/scope/index.js

@@ -0,0 +1,3 @@
+export { default as AtrulePrelude } from './atrulePrelude.js';
+export { default as Selector } from './selector.js';
+export { default as Value } from './value.js';

node_modules/css-tree/lib/syntax/scope/selector.js

@@ -0,0 +1,90 @@
+import {
+    Delim,
+    Ident,
+    Dimension,
+    Percentage,
+    Number as NumberToken,
+    Hash,
+    Colon,
+    LeftSquareBracket
+} from '../../tokenizer/index.js';
+
+const NUMBERSIGN = 0x0023;      // U+0023 NUMBER SIGN (#)
+const ASTERISK = 0x002A;        // U+002A ASTERISK (*)
+const PLUSSIGN = 0x002B;        // U+002B PLUS SIGN (+)
+const SOLIDUS = 0x002F;         // U+002F SOLIDUS (/)
+const FULLSTOP = 0x002E;        // U+002E FULL STOP (.)
+const GREATERTHANSIGN = 0x003E; // U+003E GREATER-THAN SIGN (>)
+const VERTICALLINE = 0x007C;    // U+007C VERTICAL LINE (|)
+const TILDE = 0x007E;           // U+007E TILDE (~)
+
+function onWhiteSpace(next, children) {
+    if (children.last !== null && children.last.type !== 'Combinator' &&
+        next !== null && next.type !== 'Combinator') {
+        children.push({  // FIXME: this.Combinator() should be used instead
+            type: 'Combinator',
+            loc: null,
+            name: ' '
+        });
+    }
+}
+
+function getNode() {
+    switch (this.tokenType) {
+        case LeftSquareBracket:
+            return this.AttributeSelector();
+
+        case Hash:
+            return this.IdSelector();
+
+        case Colon:
+            if (this.lookupType(1) === Colon) {
+                return this.PseudoElementSelector();
+            } else {
+                return this.PseudoClassSelector();
+            }
+
+        case Ident:
+            return this.TypeSelector();
+
+        case NumberToken:
+        case Percentage:
+            return this.Percentage();
+
+        case Dimension:
+            // throws when .123ident
+            if (this.charCodeAt(this.tokenStart) === FULLSTOP) {
+                this.error('Identifier is expected', this.tokenStart + 1);
+            }
+            break;
+
+        case Delim: {
+            const code = this.charCodeAt(this.tokenStart);
+
+            switch (code) {
+                case PLUSSIGN:
+                case GREATERTHANSIGN:
+                case TILDE:
+                case SOLIDUS:  // /deep/
+                    return this.Combinator();
+
+                case FULLSTOP:
+                    return this.ClassSelector();
+
+                case ASTERISK:
+                case VERTICALLINE:
+                    return this.TypeSelector();
+
+                case NUMBERSIGN:
+                    return this.IdSelector();
+            }
+
+            break;
+        }
+    }
+};
+
+export default {
+    onWhiteSpace,
+    getNode
+};

node_modules/css-tree/lib/syntax/scope/value.js

@@ -0,0 +1,25 @@
+import getNode from './default.js';
+import expressionFn from '../function/expression.js';
+import varFn from '../function/var.js';
+
+function isPlusMinusOperator(node) {
+    return (
+        node !== null &&
+        node.type === 'Operator' &&
+        (node.value[node.value.length - 1] === '-' || node.value[node.value.length - 1] === '+')
+    );
+}
+
+export default {
+    getNode,
+    onWhiteSpace(next, children) {
+        if (isPlusMinusOperator(next)) {
+            next.value = ' ' + next.value;
+        }
+        if (isPlusMinusOperator(children.last)) {
+            children.last.value += ' ';
+        }
+    },
+    'expression': expressionFn,
+    'var': varFn
+};

node_modules/css-tree/lib/tokenizer/OffsetToLocation.js

@@ -0,0 +1,87 @@
+import { adoptBuffer } from './adopt-buffer.js';
+import { isBOM } from './char-code-definitions.js';
+
+const N = 10;
+const F = 12;
+const R = 13;
+
+function computeLinesAndColumns(host) {
+    const source = host.source;
+    const sourceLength = source.length;
+    const startOffset = source.length > 0 ? isBOM(source.charCodeAt(0)) : 0;
+    const lines = adoptBuffer(host.lines, sourceLength);
+    const columns = adoptBuffer(host.columns, sourceLength);
+    let line = host.startLine;
+    let column = host.startColumn;
+
+    for (let i = startOffset; i < sourceLength; i++) {
+        const code = source.charCodeAt(i);
+
+        lines[i] = line;
+        columns[i] = column++;
+
+        if (code === N || code === R || code === F) {
+            if (code === R && i + 1 < sourceLength && source.charCodeAt(i + 1) === N) {
+                i++;
+                lines[i] = line;
+                columns[i] = column;
+            }
+
+            line++;
+            column = 1;
+        }
+    }
+
+    lines[sourceLength] = line;
+    columns[sourceLength] = column;
+
+    host.lines = lines;
+    host.columns = columns;
+    host.computed = true;
+}
+
+export class OffsetToLocation {
+    constructor() {
+        this.lines = null;
+        this.columns = null;
+        this.computed = false;
+    }
+    setSource(source, startOffset = 0, startLine = 1, startColumn = 1) {
+        this.source = source;
+        this.startOffset = startOffset;
+        this.startLine = startLine;
+        this.startColumn = startColumn;
+        this.computed = false;
+    }
+    getLocation(offset, filename) {
+        if (!this.computed) {
+            computeLinesAndColumns(this);
+        }
+
+        return {
+            source: filename,
+            offset: this.startOffset + offset,
+            line: this.lines[offset],
+            column: this.columns[offset]
+        };
+    }
+    getLocationRange(start, end, filename) {
+        if (!this.computed) {
+            computeLinesAndColumns(this);
+        }
+
+        return {
+            source: filename,
+            start: {
+                offset: this.startOffset + start,
+                line: this.lines[start],
+                column: this.columns[start]
+            },
+            end: {
+                offset: this.startOffset + end,
+                line: this.lines[end],
+                column: this.columns[end]
+            }
+        };
+    }
+};