diff --git a/lib/drawer/class_list_item.dart b/lib/drawer/class_list_item.dart
index d27d5fb3ce09a9e96175ca01982ce7308d701b23..63d31fb0bdd248801cf60a3b33e41ed0267e8e27 100644
--- a/lib/drawer/class_list_item.dart
+++ b/lib/drawer/class_list_item.dart
@@ -25,9 +25,8 @@ class _ClassListItemState extends State<ClassListItem> {
       widget.appContext.profile.value!.selectedClasses;
   bool get isSelected => selectedClasses.contains(widget.cls.id);
 
-  List<Lecture>? get lectures => widget.appContext.lectures == null
-      ? null
-      : widget.appContext.lectures!.where(isRelevantLecture).toList();
+  List<Lecture>? get lectures =>
+      widget.appContext.lectures?.where(isRelevantLecture).toList();
 
   bool isRelevantLecture(Lecture lecture) {
     return lecture.code.startsWith(widget.cls.code);
diff --git a/lib/timetable/lesson_chip.dart b/lib/timetable/lesson_chip.dart
index ab0bb977c03c8ea9e8db88c5611ab1720de5a073..2847db3389d56642dde2064a133c27b92c7d0c96 100644
--- a/lib/timetable/lesson_chip.dart
+++ b/lib/timetable/lesson_chip.dart
@@ -16,10 +16,10 @@ class LessonChip extends StatelessWidget {
     return pressable ? theme.primaryColor : theme.iconTheme.color!;
   }
 
-  static MaterialStateColor getTextColor(BuildContext context) =>
-      MaterialStateColor.resolveWith((states) => getTextColorOfState(
+  static WidgetStateColor getTextColor(BuildContext context) =>
+      WidgetStateColor.resolveWith((states) => getTextColorOfState(
             context,
-            pressable: !states.contains(MaterialState.disabled),
+            pressable: !states.contains(WidgetState.disabled),
           ));
 
   @override
diff --git a/lib/timetable/period_background.dart b/lib/timetable/period_background.dart
index e836703b85f9f790f7ed630b90f3800a46a0072b..78ca2c630e0731e5b965ec1d349dcf0fe1a2d7b6 100644
--- a/lib/timetable/period_background.dart
+++ b/lib/timetable/period_background.dart
@@ -18,7 +18,7 @@ class PeriodBackground extends StatelessWidget {
       offset: Offset(0, start * LessonWidget.zoom),
       child: Container(
         decoration: BoxDecoration(
-          color: Theme.of(context).colorScheme.surfaceVariant,
+          color: Theme.of(context).colorScheme.surfaceContainerHighest,
         ),
         height: (end - start) * LessonWidget.zoom,
       ),
diff --git a/lib/toolbar/toolbar.dart b/lib/toolbar/toolbar.dart
index 1273b0a29d8497611d91b2d3e56c29bf57022e37..b8932d5827a192d28565fae19f6add71b25f648d 100644
--- a/lib/toolbar/toolbar.dart
+++ b/lib/toolbar/toolbar.dart
@@ -16,7 +16,7 @@ class _ToolbarState extends State<Toolbar> {
   @override
   Widget build(BuildContext context) {
     return Container(
-      color: Theme.of(context).colorScheme.background,
+      color: Theme.of(context).colorScheme.surface,
       child: Row(
         mainAxisAlignment: MainAxisAlignment.center,
         children: [
diff --git a/lib/untis/element.dart b/lib/untis/element.dart
index f75503f6cfdfe109a57014dee7ea688717d389ec..c3fcd4951fbf0814da1cf65783d5170179349ab4 100644
--- a/lib/untis/element.dart
+++ b/lib/untis/element.dart
@@ -10,7 +10,7 @@ mixin UntisMixin {
   String toString() => name;
 
   @override
-  bool operator ==(dynamic other) {
+  bool operator ==(Object other) {
     if (other is! UntisElement) return false;
 
     return other.hashCode == hashCode;