diff --git a/pkg/display/types.go b/pkg/display/types.go
new file mode 100644
index 0000000..c1fd64b
--- /dev/null
+++ b/pkg/display/types.go
@@ -0,0 +1,9 @@
+// pkg/display/types.go
+package display
+
+// EventSource abstracts the application event system (Wails insulation for WSEventManager).
+// WSEventManager receives this instead of calling application.Get() directly.
+type EventSource interface {
+	OnThemeChange(handler func(isDark bool)) func()
+	Emit(name string, data ...any) bool
+}