feat: add clear color method and update theme background for macOS dark mode

src/app.rs

@@ -346,6 +346,10 @@ impl eframe::App for BogusMipsApp {
     fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
         self.ui(ctx);
     }
+
+    fn clear_color(&self, _visuals: &egui::Visuals) -> [f32; 4] {
+        theme::BACKGROUND.to_normalized_gamma_f32()
+    }
 }
 
 impl BogusMipsApp {
@@ -435,6 +439,16 @@ mod tests {
         let _ = ctx.run(egui::RawInput::default(), |ctx| app.ui(ctx));
     }
 
+    #[test]
+    fn uses_macos_dark_background() {
+        let ctx = egui::Context::default();
+        let _app = BogusMipsApp::with_context(&ctx, None);
+        let visuals = ctx.style().visuals.clone();
+        let expected = egui::Color32::from_rgb(0x2f, 0x31, 0x33);
+        assert_eq!(visuals.panel_fill, expected);
+        assert_eq!(visuals.window_fill, expected);
+    }
+
     #[test]
     fn renders_welcome_screen() {
         let ctx = egui::Context::default();

src/ui/theme.rs

@@ -1,11 +1,13 @@
 use eframe::egui::{self, Color32};
 
+/// Window and panel background, matching macOS dark mode.
+pub const BACKGROUND: Color32 = Color32::from_rgb(0x2f, 0x31, 0x33);
+
 pub fn apply_dark(ctx: &egui::Context) {
     ctx.set_theme(egui::Theme::Dark);
     ctx.style_mut_of(egui::Theme::Dark, |style| {
-        let bg = Color32::from_rgb(0x1e, 0x1e, 0x22);
-        style.visuals.panel_fill = bg;
-        style.visuals.window_fill = bg;
+        style.visuals.panel_fill = BACKGROUND;
+        style.visuals.window_fill = BACKGROUND;
         style.visuals.override_text_color = Some(Color32::from_rgb(0xe6, 0xe6, 0xe6));
     });
 }