Update index.html

index.html

@@ -48,12 +48,14 @@
             margin: 0;
             display: flex;
             flex-direction: column;
+            overflow: hidden;
         }
 
         .window.fullscreen .window-body {
             flex-grow: 1;
             display: flex;
             flex-direction: column;
+            min-height: 0;
         }
 
         .window.fullscreen .chat-box {