feat: add fade-out animation on dismiss for smooth visual exit

Without this, app.quit() destroys windows instantly, creating a jarring
pop-out. Now all windows fade out over 250ms (matching the fade-in)
before the app exits. Uses the same CSS opacity transition — just
removes the "visible" class and defers quit via glib timeout.

CHANGELOG.md

@@ -7,7 +7,7 @@ Format based on [Keep a Changelog](https://keepachangelog.com/).
 
 ### Added
 
-- Fade-in animation (250ms ease-in) for panel and wallpaper windows via CSS opacity transition
+- Fade-in/fade-out animation (250ms ease-in) for panel and wallpaper windows via CSS opacity transition
 
 ### Fixed
 

Cargo.lock

@@ -805,7 +805,7 @@ dependencies = [
 
 [[package]]
 name = "moonset"
-version = "0.4.0"
+version = "0.4.1"
 dependencies = [
  "dirs",
  "env_logger",

src/panel.rs

@@ -13,7 +13,7 @@ use std::io::Write;
 use std::os::unix::fs::OpenOptionsExt;
 use std::path::{Path, PathBuf};
 use std::rc::Rc;
-use std::time::SystemTime;
+use std::time::{Duration, SystemTime};
 
 use crate::i18n::{load_strings, Strings};
 use crate::power::{self, PowerError};
@@ -247,6 +247,17 @@ fn apply_blur(texture: &gdk::Texture, sigma: f32) -> gdk::Texture {
     mem_texture.upcast()
 }
 
+/// Fade out all windows and quit the app after the CSS transition completes.
+fn fade_out_and_quit(app: &gtk::Application) {
+    for window in app.windows() {
+        window.remove_css_class("visible");
+    }
+    let app = app.clone();
+    glib::timeout_add_local_once(Duration::from_millis(250), move || {
+        app.quit();
+    });
+}
+
 /// Create a wallpaper-only window for secondary monitors.
 pub fn create_wallpaper_window(texture: &gdk::Texture, app: &gtk::Application) -> gtk::ApplicationWindow {
     let window = gtk::ApplicationWindow::builder()
@@ -303,7 +314,7 @@ pub fn create_panel_window(texture: &gdk::Texture, app: &gtk::Application) -> gt
         #[weak]
         app,
         move |_, _, _, _| {
-            app.quit();
+            fade_out_and_quit(&app);
         }
     ));
     background.add_controller(click_controller);
@@ -373,7 +384,7 @@ pub fn create_panel_window(texture: &gdk::Texture, app: &gtk::Application) -> gt
         glib::Propagation::Proceed,
         move |_, keyval, _, _| {
             if keyval == gdk::Key::Escape {
-                app.quit();
+                fade_out_and_quit(&app);
                 glib::Propagation::Stop
             } else {
                 glib::Propagation::Proceed
@@ -593,7 +604,7 @@ fn execute_action(
             match result {
                 Ok(Ok(())) => {
                     if quit_after {
-                        app.quit();
+                        fade_out_and_quit(&app);
                     }
                 }
                 Ok(Err(e)) => {