Add favicons (#150)

Author: Lilfaen

src/demo/apple-touch-icon.png

@@ -21,6 +21,13 @@ function gtag() { dataLayer.push(arguments); }
     <link href="https://css.gg/css?=|moon|sun" rel="stylesheet">
     <link rel="stylesheet" href="./css/style.css">
     <link rel="stylesheet" href="./css/toggle-dark.css">
+
+    <!-- Favicons -->
+    <link rel="apple-touch-icon" sizes="180x180" href="apple-touch-icon.png">
+    <link rel="icon" type="image/png" sizes="16x16" href="favicon-16x16.png">
+    <link rel="icon" type="image/png" sizes="32x32" href="favicon-32x32.png">
+    <link rel="mask-icon" href="icon.svg" color="#fb8c00">
+
     <script type="text/javascript" src="./js/script.js" defer></script>
     <script type="text/javascript" src="./js/accordion.js" defer></script>
     <script type="text/javascript" src="./js/toggle-dark.js" defer></script>