Added favicon images.

index.html

@@ -8,6 +8,14 @@
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>Pokémon GO Level Calculator</title>
+
+  <!-- Favicon set -->
+  <link rel="icon" type="image/x-icon" href="favicon.ico">
+  <link rel="icon" type="image/png" sizes="32x32" href="pogo-32.png">
+  <link rel="icon" type="image/png" sizes="192x192" href="pogo-192.png">
+  <link rel="apple-touch-icon" sizes="180x180" href="pogo-180.png">
+  <link rel="icon" type="image/png" sizes="512x512" href="pogo-512.png">
+
   <script src="https://cdn.tailwindcss.com"></script>
   <style>
     body { font-family: 'Inter', sans-serif; }