diff --git a/CHANGELOG.md b/CHANGELOG.md
index 324554a..7f07561 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/).
 
 ## [0.4.1] - 2026-03-28
 
+### Added
+
+- Fade-in animation (250ms ease-in) for panel and wallpaper windows via CSS opacity transition
+
 ### Fixed
 
 - Fix pixel format mismatch in blur path — `texture.download()` yields BGRA but was passed to `RgbaImage` without channel swap, now explicitly converts B↔R
diff --git a/resources/style.css b/resources/style.css
index 574e4d7..b6e6265 100644
--- a/resources/style.css
+++ b/resources/style.css
@@ -6,11 +6,23 @@ window.panel {
     background-color: @theme_bg_color;
     background-size: cover;
     background-position: center;
+    opacity: 0;
+    transition: opacity 250ms ease-in;
+}
+
+window.panel.visible {
+    opacity: 1;
 }
 
 /* Wallpaper-only window for secondary monitors */
 window.wallpaper {
     background-color: @theme_bg_color;
+    opacity: 0;
+    transition: opacity 250ms ease-in;
+}
+
+window.wallpaper.visible {
+    opacity: 1;
 }
 
 /* Round avatar image */