macOS: UI fixes for dark mode

Source/Core/DolphinQt/Config/SettingsWindow.h

@@ -8,6 +8,7 @@
 class QStackedWidget;
 class QListWidget;
 class MainWindow;
+class QEvent;
 
 // A settings window with a QListWidget to switch between panes of a QStackedWidget.
 class StackedSettingsWindow : public QDialog
@@ -27,9 +28,15 @@ protected:
   // For derived classes to call after they create their settings panes.
   void OnDoneCreatingPanes();
 
+  void changeEvent(QEvent* event) override;
+
 private:
-  QStackedWidget* m_stacked_panes;
-  QListWidget* m_navigation_list;
+  void UpdateNavigationListStyle();
+
+  QStackedWidget* m_stacked_panes = nullptr;
+  QListWidget* m_navigation_list = nullptr;
+  int m_list_item_padding = 0;
+  bool m_handling_theme_change = false;
 };
 
 enum class SettingsWindowPaneIndex : int