diff --git a/lib/widgets/app_intro_page.dart b/lib/widgets/app_intro_page.dart
index 04ee386..ab3fc2f 100644
--- a/lib/widgets/app_intro_page.dart
+++ b/lib/widgets/app_intro_page.dart
@@ -43,15 +43,17 @@ class _AppIntroPageSelector extends StatelessWidget {
   final OnIntroFinish onFinish;
 
   void _handleArrowButtonPress(BuildContext context, int delta) {
-    final TabController controller = DefaultTabController.of(context)!;
-    if (!controller.indexIsChanging)
+    final TabController? controller = DefaultTabController.of(context);
+    if (controller != null && !controller.indexIsChanging)
       controller.animateTo(
           (controller.index + delta).clamp(0, items(context).length - 1));
   }
 
   @override
   Widget build(BuildContext context) {
-    final TabController controller = DefaultTabController.of(context)!;
+    final TabController? controller = DefaultTabController.of(context);
+    if (controller == null) return const SizedBox.shrink();
+
     final ThemeData theme = Theme.of(context);
     final Color color = theme.colorScheme.secondary;
     final TextStyle titleStyle =