diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..9b78034
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+  RUSTFLAGS: "-Dwarnings"
+
+jobs:
+  check:
+    name: Check
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+
+      - name: Cache Rust dependencies
+        uses: Swatinem/rust-cache@v2
+
+      - name: Format check
+        run: cargo fmt --check
+
+      - name: Clippy
+        run: cargo clippy --all-targets --all-features -- -D warnings
+
+      - name: Build
+        run: cargo build --verbose
+
+      - name: Test
+        run: cargo test --verbose
diff --git a/src/animation.rs b/src/animation.rs
index f3a954e..b01506b 100644
--- a/src/animation.rs
+++ b/src/animation.rs
@@ -9,7 +9,6 @@ use windows::Win32::UI::WindowsAndMessaging::{
     SWP_SHOWWINDOW, SetWindowLongPtrW, SetWindowPos, WS_EX_COMPOSITED,
 };
 
-use crate::error::AnimationError;
 use crate::tracking::WindowBounds;
 
 /// Slide direction
@@ -106,7 +105,7 @@ pub fn run_animation(
     bounds: &WindowBounds,
     work_area: &RECT,
     slide_in: bool,
-) -> Result<(), AnimationError> {
+) {
     let duration = Duration::from_millis(config.duration_ms as u64);
     let start = Instant::now();
 
@@ -198,8 +197,6 @@ pub fn run_animation(
         let _ = InvalidateRect(Some(hwnd), None, true);
         SetWindowLongPtrW(hwnd, GWL_EXSTYLE, original_exstyle);
     }
-
-    Ok(())
 }
 
 #[cfg(test)]
diff --git a/src/error.rs b/src/error.rs
index cf3efc7..7b22f64 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -2,13 +2,6 @@
 
 use thiserror::Error;
 
-/// Animation errors (graceful degradation)
-#[derive(Debug, Error)]
-pub enum AnimationError {
-    #[error("GetMonitorInfo failed")]
-    MonitorInfo,
-}
-
 /// Focus tracking errors (graceful degradation)
 #[derive(Debug, Error)]
 pub enum FocusError {
@@ -23,12 +16,6 @@ pub enum FocusError {
 mod tests {
     use super::*;
 
-    #[test]
-    fn test_animation_error_display() {
-        let err = AnimationError::MonitorInfo;
-        assert_eq!(err.to_string(), "GetMonitorInfo failed");
-    }
-
     #[test]
     fn test_focus_error_display() {
         let err = FocusError::HookInstall;
diff --git a/src/main.rs b/src/main.rs
index a0ce289..e4e1f42 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -186,9 +186,7 @@ fn toggle_window() {
         }
 
         // 4. Slide out
-        if let Err(e) = run_animation(hwnd, &config, direction, &bounds, &work_area, false) {
-            error!("Animation error: {e}");
-        }
+        run_animation(hwnd, &config, direction, &bounds, &work_area, false);
         WINDOW_VISIBLE.store(false, Ordering::SeqCst);
         info!(direction = ?direction, "Window: focus restored → slide out → hidden");
     } else {
@@ -205,9 +203,7 @@ fn toggle_window() {
         focus::save_previous(prev);
 
         // 4. Slide in
-        if let Err(e) = run_animation(hwnd, &config, direction, &bounds, &work_area, true) {
-            error!("Animation error: {e}");
-        }
+        run_animation(hwnd, &config, direction, &bounds, &work_area, true);
         let _ = unsafe { SetForegroundWindow(hwnd) };
         focus::set_target(hwnd);
         if let Err(e) = focus::install_hook(hwnd) {
@@ -250,9 +246,7 @@ fn handle_focus_lost() {
     let direction = tracking::calc_direction(&bounds, &work_area);
 
     let config = AnimConfig::default();
-    if let Err(e) = run_animation(target, &config, direction, &bounds, &work_area, false) {
-        error!("Animation error: {e}");
-    }
+    run_animation(target, &config, direction, &bounds, &work_area, false);
     WINDOW_VISIBLE.store(false, Ordering::SeqCst);
     info!(direction = ?direction, "Window: focus lost → hidden");
 }
diff --git a/src/tracking.rs b/src/tracking.rs
index d63d6aa..a7a6811 100644
--- a/src/tracking.rs
+++ b/src/tracking.rs
@@ -57,7 +57,7 @@ pub fn is_tracked_valid() -> bool {
 /// Returns captured bounds, or None if GetWindowRect fails
 pub fn save_bounds(hwnd: HWND) -> Option<WindowBounds> {
     let mut rect = RECT::default();
-    if !unsafe { GetWindowRect(hwnd, &mut rect) }.is_ok() {
+    if unsafe { GetWindowRect(hwnd, &mut rect) }.is_err() {
         return None;
     }
 
@@ -82,8 +82,9 @@ pub fn load_bounds() -> Option<WindowBounds> {
     }
 }
 
-/// Clear stored bounds
-pub fn clear_bounds() {
+/// Clear stored bounds (test-only)
+#[cfg(test)]
+fn clear_bounds() {
     let ptr = STORED_BOUNDS.swap(null_mut(), Ordering::SeqCst);
     if !ptr.is_null() {
         // Safety: ptr was created by Box::into_raw