Polished layout and icons

lib/app.dart

@@ -94,7 +94,7 @@ class _AppState extends State<App> {
         PersistentBottomNavBarItem(
           activeColorPrimary: Theme.of(context).primaryColor,
           inactiveColorPrimary: Theme.of(context).colorScheme.secondary,
-          icon: const Icon(Icons.more_horiz),
+          icon: const Icon(Icons.apps),
           title: "Mehr"
         ),
       ],