Update public/index.html

Test

public/index.html

@@ -89,6 +89,15 @@
       border-color: #4CAF50;
     }
 
+    canvas {
+      position: fixed;
+      top: 0;
+      left: 0;
+      width: 100%;
+      height: 100%;
+      z-index: 0; /* Canvas liegt hinter dem Menü */
+    }
+
   </style>
   <script src="https://unpkg.com/three@0.126.0/build/three.js"></script>
   <script src="https://unpkg.com/three@0.126.0/examples/js/loaders/GLTFLoader.js"></script>