Sync with system appearance.

crates/ui/src/icon.rs

@@ -4,7 +4,6 @@ use gpui::{
     RenderOnce, SharedString, StyleRefinement, Styled, Svg, TextStyle, TextStyleRefinement,
     WindowContext,
 };
-use windows::Win32::Foundation::NOERROR;
 
 #[derive(IntoElement)]
 pub enum IconName {

crates/ui/src/theme.rs

@@ -1,4 +1,4 @@
-use gpui::{hsla, AppContext, Global, Hsla};
+use gpui::{hsla, AppContext, Global, Hsla, WindowAppearance};
 
 pub trait ActiveTheme {
     fn theme(&self) -> &Theme;
@@ -293,7 +293,20 @@ impl Theme {
     }
 
     pub fn init(cx: &mut AppContext) {
-        cx.set_global(Theme::new())
+        cx.set_global(Theme::new());
+        Self::sync_system_appearance(cx)
+    }
+
+    /// Sync the theme with the system appearance
+    pub fn sync_system_appearance(cx: &mut AppContext) {
+        match cx.window_appearance() {
+            WindowAppearance::Dark | WindowAppearance::VibrantDark => {
+                Self::change(ThemeMode::Dark, cx)
+            }
+            WindowAppearance::Light | WindowAppearance::VibrantLight => {
+                Self::change(ThemeMode::Light, cx)
+            }
+        }
     }
 
     pub fn change(mode: ThemeMode, cx: &mut AppContext) {

crates/workspace/src/lib.rs

@@ -28,6 +28,11 @@ impl Workspace {
         _parent: Option<WeakView<Self>>,
         cx: &mut ViewContext<Self>,
     ) -> Self {
+        cx.observe_window_appearance(|_workspace, cx| {
+            Theme::sync_system_appearance(cx);
+        })
+        .detach();
+
         Workspace {
             stories: Stories::view(cx),
             notifications: Default::default(),