feat: adopt the native OS theme (#33)

Reviewed-on: #33

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ### Added
 
+- Follow the operating system's native theme on macOS, Windows and Linux (KDE, GNOME), applying the OS colors, fonts, radii and accessibility preferences.
 - Add an identity import dialog, importing an existing identity by pasting its `nsec` secret key (encrypted with a new passphrase), NIP-49 `ncryptsec` (unlocked with its passphrase), or `bunker://` NIP-46 URI
 - Add a dropdown menu on the signed-in user button in the sidebar
 - Add sign-out feature, confirmed by an alert dialog before deleting the stored session credential
@@ -17,6 +18,7 @@
 
 ### Changed
 
+- Use the built-in light/dark syntax highlighting palette instead of the Signed palette bundled in `signed.json` when the native theme is active
 - Increase the default theme corner radii from 2 to 4 and large radii from 6 to 8
 - Surface backend errors as error notifications in the workspace instead of silently dropping them
 - Break ties in repository activity lists by event id, so same-second events order deterministically
@@ -41,6 +43,7 @@
 
 ### Removed
 
+- Remove the light/dark theme pickers and the font size, corner radius, focus ring and shadow settings from the settings dialog; colors and geometry now come from the native theme
 - Remove dead code: the unused `login`/`logout` family, the unwired `SyncProgress` pipeline, `merge_pull_request`, inbox mark-read/archive APIs and the wasm32-only code paths
 
 ### Deprecated

Cargo.toml

@@ -13,9 +13,13 @@ gpui = { package = "gpui-pre", version = "0.3.8" }
 gpui_platform = { package = "gpui-pre-platform", version = "0.3.8", features = ["font-kit", "x11", "wayland"] }
 reqwest_client = { package = "gpui-pre-reqwest-client", version = "0.3.8" }
 
-# GPUI Kit
+# GPUI Kit; exact pins keep the graph on the gpui-pre 0.3.8 closure that
-gpui-component = { version = "0.7.1", features = ["tree-sitter-languages"] }
+# native-theme-gpui 0.6.1 is verified against (0.7.3 and 0.8 pin 0.3.9).
-gpui-base = "0.7.1"
+gpui-component = { version = "=0.7.1", features = ["tree-sitter-languages"] }
+gpui-base = "=0.7.1"
+
+native-theme = { version = "0.6.1", features = ["watch"] }
+native-theme-gpui = { version = "0.6.1", default-features = false, features = ["system-fonts"] }
 
 dock = { path = "crates/dock" }
 settings = { path = "crates/settings" }

crates/signed_state/src/backend.rs

@@ -1,6 +1,7 @@
 use std::collections::HashSet;
 use std::path::PathBuf;
 use std::str::FromStr;
+use std::sync::Arc;
 use std::time::{Duration, Instant};
 
 use anyhow::{Error, anyhow, bail};
@@ -24,8 +25,6 @@ use crate::repos::RepoListStore;
 use crate::state::{GitPushMode, GitPushPolicy, GitRef, PushStepStatus, SyncState};
 
 pub const USER_KEYRING: &str = "Signed Safe Storage";
-pub const NOSTR_CONNECT_TIMEOUT: u64 = 60;
-
 const PUMP_DEBOUNCE: Duration = Duration::from_millis(200);
 
 #[derive(Debug, Clone)]
@@ -199,13 +198,9 @@ impl Backend {
                 } else if content.starts_with("bunker://") {
                     let (base, keys) = extract_master_key(&content)?;
                     let uri = NostrConnectUri::parse(base)?;
-                    let mut signer = NostrConnect::new(
+                    let signer = NostrConnect::builder(uri, keys)
-                        uri,
+                        .auth_url_handler(Arc::new(SignedAuthUrlHandler))
-                        keys,
+                        .build()?;
-                        Duration::from_secs(NOSTR_CONNECT_TIMEOUT),
-                        None,
-                    )?;
-                    signer.auth_url_handler(SignedAuthUrlHandler);
 
                     this.update(cx, |this, cx| {
                         this.set_signer(signer, cx);
@@ -366,13 +361,9 @@ impl Backend {
         let write = cx.write_credentials(USER_KEYRING, "bunker", credential.as_bytes());
 
         cx.spawn(async move |this, cx| {
-            let mut signer = NostrConnect::new(
+            let signer = NostrConnect::builder(connect_uri, keys)
-                connect_uri,
+                .auth_url_handler(Arc::new(SignedAuthUrlHandler))
-                keys,
+                .build()?;
-                Duration::from_secs(NOSTR_CONNECT_TIMEOUT),
-                None,
-            )?;
-            signer.auth_url_handler(SignedAuthUrlHandler);
 
             // Verify the bunker responds before persisting the credential.
             let public_key = signer.get_public_key_async().await?;

crates/workspace/src/views/sidebar/settings_dialog.rs

@@ -1,22 +1,15 @@
-use std::cell::Cell;
 use std::path::PathBuf;
 use std::rc::Rc;
 
 use gpui::prelude::*;
-use gpui::{
+use gpui::{App, Entity, PathPromptOptions, SharedString, Subscription, Window, div, px};
-    AnyWindowHandle, App, Entity, PathPromptOptions, SharedString, Subscription, Window, div, px,
-};
 use gpui_component::button::{Button, ButtonVariants};
-use gpui_component::input::{
+use gpui_component::input::{Input, InputState};
-    Input, InputEvent, InputState, NumberInput, NumberInputEvent, StepAction,
-};
 use gpui_component::select::{Select, SelectEvent, SelectState};
 use gpui_component::separator::Separator;
-use gpui_component::setting::NumberFieldOptions;
 use gpui_component::switch::Switch;
 use gpui_component::{
-    ActiveTheme, IconName, IndexPath, Sizable, Theme, ThemeMode, ThemeRegistry, WindowExt, h_flex,
+    ActiveTheme, IconName, IndexPath, Sizable, Theme, ThemeMode, WindowExt, h_flex, v_flex,
-    v_flex,
 };
 use settings::{AppearanceMode, EventFetchingStrategy, Settings, SettingsStore};
 use signed_ui::{SelectOption, setting_block, setting_row};
@@ -31,34 +24,10 @@ fn selected_index(options: &[SelectOption], value: &str) -> Option<IndexPath> {
         .map(|row| IndexPath::default().row(row))
 }
 
-/// Registered themes split into light and dark options, light first.
-fn theme_options(cx: &App) -> (Vec<SelectOption>, Vec<SelectOption>) {
-    let registry = ThemeRegistry::global(cx);
-    let mut light = Vec::new();
-    let mut dark = Vec::new();
-    for config in registry.themes().values() {
-        let name = config.name.clone();
-        if config.mode.is_dark() {
-            dark.push(SelectOption::new(name.clone(), name));
-        } else {
-            light.push(SelectOption::new(name.clone(), name));
-        }
-    }
-    light.sort_by(|a, b| a.label().as_ref().cmp(b.label().as_ref()));
-    dark.sort_by(|a, b| a.label().as_ref().cmp(b.label().as_ref()));
-    (light, dark)
-}
-
 /// Created once when the dialog opens, so control state survives re-renders.
 struct SettingsControls {
     appearance: Entity<SelectState<Vec<SelectOption>>>,
     event_fetching: Entity<SelectState<Vec<SelectOption>>>,
-    light_theme: Entity<SelectState<Vec<SelectOption>>>,
-    dark_theme: Entity<SelectState<Vec<SelectOption>>>,
-    font_size: Entity<InputState>,
-    mono_font_size: Entity<InputState>,
-    radius: Entity<InputState>,
-    radius_lg: Entity<InputState>,
     grasp_server_input: Entity<InputState>,
     /// The effective create-repository folder, shown in a disabled input.
     default_folder: Entity<InputState>,
@@ -107,38 +76,9 @@ impl SettingsControls {
             )
         });
 
-        let (light_options, dark_options) = theme_options(cx);
-        let light_theme = cx.new(|cx| {
-            SelectState::new(
-                light_options.clone(),
-                selected_index(&light_options, &settings.theme.light_theme),
-                window,
-                cx,
-            )
-        });
-        let dark_theme = cx.new(|cx| {
-            SelectState::new(
-                dark_options.clone(),
-                selected_index(&dark_options, &settings.theme.dark_theme),
-                window,
-                cx,
-            )
-        });
-
-        let font_size = cx.new(|cx| {
-            InputState::new(window, cx).default_value(settings.theme.font_size.to_string())
-        });
-        let mono_font_size = cx.new(|cx| {
-            InputState::new(window, cx).default_value(settings.theme.mono_font_size.to_string())
-        });
-        let radius = cx
-            .new(|cx| InputState::new(window, cx).default_value(settings.theme.radius.to_string()));
-        let radius_lg = cx.new(|cx| {
-            InputState::new(window, cx).default_value(settings.theme.radius_lg.to_string())
-        });
-
         let grasp_server_input =
             cx.new(|cx| InputState::new(window, cx).placeholder("wss://relay.example.com"));
+
         let default_folder = cx.new(|cx| {
             let folder = settings
                 .create_repository
@@ -178,118 +118,9 @@ impl SettingsControls {
             }
         }));
 
-        subscriptions.push(cx.subscribe(&light_theme, |_, event, cx| {
-            if let SelectEvent::Confirm(Some(value)) = event {
-                let store = SettingsStore::global(cx);
-                store.update(cx, |store, cx| {
-                    store.edit(
-                        |settings| settings.theme.light_theme = value.to_string(),
-                        cx,
-                    );
-                });
-                apply_theme(cx);
-            }
-        }));
-
-        subscriptions.push(cx.subscribe(&dark_theme, |_, event, cx| {
-            if let SelectEvent::Confirm(Some(value)) = event {
-                let store = SettingsStore::global(cx);
-                store.update(cx, |store, cx| {
-                    store.edit(|settings| settings.theme.dark_theme = value.to_string(), cx);
-                });
-                apply_theme(cx);
-            }
-        }));
-
-        wire_number_input(
-            &font_size,
-            &mut subscriptions,
-            window.window_handle(),
-            cx,
-            NumberFieldOptions {
-                min: 10.,
-                max: 32.,
-                ..Default::default()
-            },
-            settings.theme.font_size as f64,
-            |value, cx| {
-                let store = SettingsStore::global(cx);
-                store.update(cx, |store, cx| {
-                    store.edit(|settings| settings.theme.font_size = value as f32, cx);
-                });
-                apply_theme(cx);
-            },
-        );
-
-        wire_number_input(
-            &mono_font_size,
-            &mut subscriptions,
-            window.window_handle(),
-            cx,
-            NumberFieldOptions {
-                min: 8.,
-                max: 32.,
-                ..Default::default()
-            },
-            settings.theme.mono_font_size as f64,
-            |value, cx| {
-                let store = SettingsStore::global(cx);
-                store.update(cx, |store, cx| {
-                    store.edit(|settings| settings.theme.mono_font_size = value as f32, cx);
-                });
-                apply_theme(cx);
-            },
-        );
-
-        wire_number_input(
-            &radius,
-            &mut subscriptions,
-            window.window_handle(),
-            cx,
-            NumberFieldOptions {
-                min: 0.,
-                max: 24.,
-                ..Default::default()
-            },
-            settings.theme.radius as f64,
-            |value, cx| {
-                let store = SettingsStore::global(cx);
-                store.update(cx, |store, cx| {
-                    store.edit(|settings| settings.theme.radius = value as f32, cx);
-                });
-                apply_theme(cx);
-            },
-        );
-
-        wire_number_input(
-            &radius_lg,
-            &mut subscriptions,
-            window.window_handle(),
-            cx,
-            NumberFieldOptions {
-                min: 0.,
-                max: 24.,
-                ..Default::default()
-            },
-            settings.theme.radius_lg as f64,
-            |value, cx| {
-                let store = SettingsStore::global(cx);
-                store.update(cx, |store, cx| {
-                    store.edit(|settings| settings.theme.radius_lg = value as f32, cx);
-                });
-                apply_theme(cx);
-            },
-        );
-
         Self {
             appearance,
             event_fetching,
-            light_theme,
-            dark_theme,
-            font_size,
-            mono_font_size,
-            radius,
-            radius_lg,
             grasp_server_input,
             default_folder,
             _subscriptions: subscriptions,
@@ -320,8 +151,6 @@ fn settings_view(controls: &SettingsControls, cx: &mut App) -> impl IntoElement
         .w_full()
         .child(appearance_section(controls, cx))
         .child(Separator::horizontal())
-        .child(theme_section(&settings, controls, cx))
-        .child(Separator::horizontal())
         .child(tab_bar_section(&settings, cx))
         .child(Separator::horizontal())
         .child(grasp_servers_section(&settings, controls, cx))
@@ -350,76 +179,6 @@ fn event_fetching_section(controls: &SettingsControls, cx: &App) -> impl IntoEle
     ))
 }
 
-fn theme_section(settings: &Settings, controls: &SettingsControls, cx: &App) -> impl IntoElement {
-    v_flex()
-        .gap_3()
-        .w_full()
-        .child(setting_row(
-            cx,
-            "Light Theme",
-            "The theme to use when the appearance is light.",
-            Select::new(&controls.light_theme).w_full(),
-        ))
-        .child(setting_row(
-            cx,
-            "Dark Theme",
-            "The theme to use when the appearance is dark.",
-            Select::new(&controls.dark_theme).w_full(),
-        ))
-        .child(setting_row(
-            cx,
-            "UI Font Size",
-            "Font size for the UI.",
-            NumberInput::new(&controls.font_size).w_full(),
-        ))
-        .child(setting_row(
-            cx,
-            "Editor Font Size",
-            "Font size for editor text.",
-            NumberInput::new(&controls.mono_font_size).w_full(),
-        ))
-        .child(setting_row(
-            cx,
-            "Corner Radius",
-            "The corner radius for UI elements.",
-            NumberInput::new(&controls.radius).w_full(),
-        ))
-        .child(setting_row(
-            cx,
-            "Large Corner Radius",
-            "The corner radius for large UI elements (dialogs, notifications).",
-            NumberInput::new(&controls.radius_lg).w_full(),
-        ))
-        .child(setting_row(
-            cx,
-            "Focus Ring",
-            "Draw a ring around focused controls.",
-            Switch::new("focus-ring")
-                .checked(settings.theme.focus_ring)
-                .on_click(move |checked: &bool, _window, cx| {
-                    let store = SettingsStore::global(cx);
-                    store.update(cx, |store, cx| {
-                        store.edit(|settings| settings.theme.focus_ring = *checked, cx);
-                    });
-                    apply_theme(cx);
-                }),
-        ))
-        .child(setting_row(
-            cx,
-            "Shadows",
-            "The shadow effect for UI elements.",
-            Switch::new("shadows")
-                .checked(settings.theme.shadow)
-                .on_click(move |checked: &bool, _window, cx| {
-                    let store = SettingsStore::global(cx);
-                    store.update(cx, |store, cx| {
-                        store.edit(|settings| settings.theme.shadow = *checked, cx);
-                    });
-                    apply_theme(cx);
-                }),
-        ))
-}
-
 /// Tab bar chrome, such as its next/previous tab buttons.
 fn tab_bar_section(settings: &Settings, cx: &App) -> impl IntoElement {
     v_flex().w_full().gap_3().child(setting_row(
@@ -724,79 +483,6 @@ fn choose_default_folder(default_folder: &Entity<InputState>, window: &mut Windo
     .detach();
 }
 
-/// Step actions clamp and persist the value; typed changes parse, clamp and persist.
-fn wire_number_input(
-    state: &Entity<InputState>,
-    subscriptions: &mut Vec<Subscription>,
-    window_handle: AnyWindowHandle,
-    cx: &mut App,
-    options: NumberFieldOptions,
-    initial: f64,
-    on_change: impl Fn(f64, &mut App) + 'static,
-) {
-    let on_change = Rc::new(on_change);
-    let initial_value = Rc::new(Cell::new(initial));
-    let (min, max, step) = (options.min, options.max, options.step);
-
-    subscriptions.push(cx.subscribe(&state.clone(), {
-        let state = state.clone();
-        let initial_value = initial_value.clone();
-        let on_change = on_change.clone();
-        move |_, event: &NumberInputEvent, cx| {
-            let NumberInputEvent::Step(action) = event;
-            let value = state.read(cx).value();
-            if let Ok(value) = value.parse::<f64>() {
-                let new_value = match action {
-                    StepAction::Increment => value + step,
-                    StepAction::Decrement => value - step,
-                };
-                let clamped = new_value.clamp(min, max);
-                window_handle
-                    .update(cx, |_, window, cx| {
-                        state.update(cx, |input, cx| {
-                            input.set_value(SharedString::from(clamped.to_string()), window, cx);
-                        });
-                    })
-                    .ok();
-                initial_value.set(clamped);
-                on_change(clamped, cx);
-            }
-        }
-    }));
-
-    subscriptions.push(cx.subscribe(&state.clone(), {
-        let state = state.clone();
-        let initial_value = initial_value.clone();
-        let on_change = on_change.clone();
-        move |_, event: &InputEvent, cx| {
-            if matches!(event, InputEvent::Change) {
-                let value = state.read(cx).value();
-                if value == initial_value.get().to_string() {
-                    return;
-                }
-                if let Ok(parsed) = value.parse::<f64>() {
-                    let clamped = parsed.clamp(min, max);
-                    initial_value.set(clamped);
-                    on_change(clamped, cx);
-                    if clamped != parsed {
-                        window_handle
-                            .update(cx, |_, window, cx| {
-                                state.update(cx, |input, cx| {
-                                    input.set_value(
-                                        SharedString::from(clamped.to_string()),
-                                        window,
-                                        cx,
-                                    );
-                                });
-                            })
-                            .ok();
-                    }
-                }
-            }
-        }
-    }));
-}
-
 fn apply_appearance(appearance: AppearanceMode, cx: &mut App) {
     match appearance {
         AppearanceMode::System => Theme::sync_system_appearance(None, cx),
@@ -804,33 +490,3 @@ fn apply_appearance(appearance: AppearanceMode, cx: &mut App) {
         AppearanceMode::Dark => Theme::change(ThemeMode::Dark, None, cx),
     }
 }
-
-fn apply_theme(cx: &mut App) {
-    let store = SettingsStore::global(cx);
-    let settings = store.read(cx).settings().theme.clone();
-
-    let registry = ThemeRegistry::global(cx);
-    let light_config = registry
-        .themes()
-        .get(settings.light_theme.as_str())
-        .cloned();
-    let dark_config = registry.themes().get(settings.dark_theme.as_str()).cloned();
-    let mode = Theme::global(cx).mode;
-
-    let theme = Theme::global_mut(cx);
-    theme.radius = px(settings.radius);
-    theme.radius_lg = px(settings.radius_lg);
-    theme.focus_ring = settings.focus_ring;
-    theme.shadow = settings.shadow;
-    theme.font_size = px(settings.font_size);
-    theme.mono_font_size = px(settings.mono_font_size);
-    if let Some(config) = light_config {
-        theme.light_theme = config;
-    }
-    if let Some(config) = dark_config {
-        theme.dark_theme = config;
-    }
-
-    // Re-apply the active mode so the updated configs take effect.
-    Theme::change(mode, None, cx);
-}

desktop/Cargo.toml

@@ -38,6 +38,9 @@ gpui.workspace = true
 gpui_platform.workspace = true
 dock = { workspace = true }
 gpui-component.workspace = true
+native-theme.workspace = true
+native-theme-gpui.workspace = true
+flume.workspace = true
 reqwest_client.workspace = true
 tracing.workspace = true
 tracing-subscriber.workspace = true

desktop/src/main.rs

@@ -5,7 +5,9 @@ use dock::TAB_BAR_HEIGHT;
 use gpui::*;
 use gpui_component::{Theme, ThemeMode, ThemeRegistry, theme};
 use gpui_platform::application;
-use settings::{AppearanceMode, SettingsStore};
+use native_theme::watch::ThemeSubscription;
+use native_theme_gpui::{SystemTheme, apply_system_theme};
+use settings::{AppearanceMode, Settings, SettingsStore};
 
 actions!(signed, [Quit]);
 
@@ -25,57 +27,64 @@ fn main() {
             // The persisted settings must load before the theme is applied.
             let store = cx.new(|cx| SettingsStore::new(paths::settings_file(), cx));
             SettingsStore::set_global(store.clone(), cx);
-            let settings = store.read(cx).settings().clone();
 
-            let registry = ThemeRegistry::global_mut(cx);
+            let settings = store.read(cx).settings().clone();
-            for (name, content) in Assets.themes() {
+            {
-                if let Err(err) = registry.load_themes_from_str(&content) {
+                let registry = ThemeRegistry::global_mut(cx);
-                    tracing::error!("Failed to load theme {name}: {err}");
+                for (name, content) in Assets.themes() {
+                    if let Err(err) = registry.load_themes_from_str(&content) {
+                        tracing::error!("Failed to load theme {name}: {err}");
+                    }
                 }
             }
-            let light_theme = registry
-                .themes()
-                .get(settings.theme.light_theme.as_str())
-                .cloned();
-            let dark_theme = registry
-                .themes()
-                .get(settings.theme.dark_theme.as_str())
-                .cloned();
 
-            let theme = Theme::global_mut(cx);
+            match apply_native_theme(&settings, cx) {
-            theme.radius = px(settings.theme.radius);
+                Ok(()) => start_theme_watcher(cx),
-            theme.radius_lg = px(settings.theme.radius_lg);
+                Err(error) => {
-            theme.focus_ring = settings.theme.focus_ring;
+                    tracing::warn!("native theme unavailable ({error})");
-            theme.shadow = settings.theme.shadow;
-            theme.font_size = px(settings.theme.font_size);
-            theme.mono_font_size = px(settings.theme.mono_font_size);
 
-            if let Some(light) = light_theme {
+                    let registry = ThemeRegistry::global_mut(cx);
-                theme.light_theme = light;
+                    let light_theme = registry
-            } else {
+                        .themes()
-                tracing::warn!(
+                        .get(settings.theme.light_theme.as_str())
-                    "{} theme is missing from the registry",
+                        .cloned();
-                    settings.theme.light_theme
-                );
-            }
 
-            if let Some(dark) = dark_theme {
+                    let dark_theme = registry
-                theme.dark_theme = dark;
+                        .themes()
-            } else {
+                        .get(settings.theme.dark_theme.as_str())
-                tracing::warn!(
+                        .cloned();
-                    "{} theme is missing from the registry",
-                    settings.theme.dark_theme
-                );
-            }
 
-            match settings.appearance {
+                    let theme = Theme::global_mut(cx);
-                AppearanceMode::System => Theme::sync_system_appearance(None, cx),
+                    theme.radius = px(settings.theme.radius);
-                AppearanceMode::Light => Theme::change(ThemeMode::Light, None, cx),
+                    theme.radius_lg = px(settings.theme.radius_lg);
-                AppearanceMode::Dark => Theme::change(ThemeMode::Dark, None, cx),
+                    theme.focus_ring = settings.theme.focus_ring;
+                    theme.shadow = settings.theme.shadow;
+                    theme.font_size = px(settings.theme.font_size);
+                    theme.mono_font_size = px(settings.theme.mono_font_size);
+
+                    if let Some(light) = light_theme {
+                        theme.light_theme = light;
+                    } else {
+                        tracing::warn!("{} theme is missing", settings.theme.light_theme);
+                    }
+
+                    if let Some(dark) = dark_theme {
+                        theme.dark_theme = dark;
+                    } else {
+                        tracing::warn!("{} theme is missing", settings.theme.dark_theme);
+                    }
+
+                    match settings.appearance {
+                        AppearanceMode::System => Theme::sync_system_appearance(None, cx),
+                        AppearanceMode::Light => Theme::change(ThemeMode::Light, None, cx),
+                        AppearanceMode::Dark => Theme::change(ThemeMode::Dark, None, cx),
+                    }
+                }
             }
 
             std::fs::create_dir_all(paths::nostr_dir()).ok();
             std::fs::create_dir_all(paths::repos_dir()).ok();
+
             signed_state::init(
                 paths::nostr_dir(),
                 paths::repos_dir().clone(),
@@ -115,3 +124,62 @@ fn main() {
             cx.activate(true);
         });
 }
+
+/// Apply the OS theme to the app, scaling the font size to match the system font size.
+fn apply_native_theme(settings: &Settings, cx: &mut App) -> native_theme::Result<()> {
+    let mut system = SystemTheme::from_system()?;
+    let native = system.light.defaults.font.size;
+    if native > 0.0 {
+        let scaling = settings.theme.font_size / native;
+        system.accessibility.text_scaling_factor *= scaling;
+    }
+
+    apply_system_theme(&system, cx);
+
+    match settings.appearance {
+        AppearanceMode::System => Theme::sync_system_appearance(None, cx),
+        AppearanceMode::Light => Theme::change(ThemeMode::Light, None, cx),
+        AppearanceMode::Dark => Theme::change(ThemeMode::Dark, None, cx),
+    }
+
+    Ok(())
+}
+
+/// Holds the watcher subscription so it lives as long as the app.
+struct ThemeWatcher {
+    _subscription: ThemeSubscription,
+}
+
+impl Global for ThemeWatcher {}
+
+/// Re-apply the OS theme whenever it changes at runtime.
+fn start_theme_watcher(cx: &mut App) {
+    let (sender, receiver) = flume::unbounded();
+    match native_theme::watch::on_theme_change(move |event| {
+        if let Err(error) = sender.send(event) {
+            tracing::warn!("theme change dropped ({error})");
+        }
+    }) {
+        Ok(subscription) => {
+            cx.set_global(ThemeWatcher {
+                _subscription: subscription,
+            });
+            cx.spawn(async move |cx| {
+                while receiver.recv_async().await.is_ok() {
+                    tracing::info!("OS theme changed; re-applying");
+                    cx.update(|cx| {
+                        let store = SettingsStore::global(cx);
+                        let settings = store.read(cx).settings().clone();
+                        if let Err(error) = apply_native_theme(&settings, cx) {
+                            tracing::warn!("failed to apply updated OS theme ({error})");
+                        }
+                    });
+                }
+            })
+            .detach();
+        }
+        Err(error) => {
+            tracing::warn!("OS theme watching unavailable ({error})")
+        }
+    }
+}