adjust instructions for clarity

css/main.css

@@ -70,8 +70,9 @@ body {
     top: 50%;
     left: 50%;
     transform: translate(-50%, -50%);
-    width: 50%;
-    height: 50%;
+    width: 90%;
+    max-width: 600px;
+    height: 90%;
 }
 
 .no-gamepad #a-button path {

index.html

@@ -78,6 +78,7 @@
 					</g>
 				</g>
 			</g>
+			<text x="50%" y="340" dominant-baseline="middle" text-anchor="middle" font-size="28">Press a gamepad button</text>
 		</svg>
 	</div>
 	<div id="gamepad"></div>