diff --git a/src-tauri/Cargo.toml b/src-tauri/Cargo.toml
index 3ee7131..eee9a2a 100644
--- a/src-tauri/Cargo.toml
+++ b/src-tauri/Cargo.toml
@@ -60,6 +60,7 @@ keyring = "4"
 windows-sys = { version = "0.61", features = [
   "Win32_Security_Cryptography",
   "Win32_Foundation",
+  "Win32_Graphics_Dwm",
   "Win32_Security",
   "Win32_Security_Authorization",
   "Win32_Storage_FileSystem",
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 7b7f810..9ae358c 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -9,4 +9,5 @@ pub mod ipc;
 pub mod private_file;
 pub mod qr;
 pub mod sync;
+pub mod title_bar;
 pub mod words;
diff --git a/src-tauri/src/main.rs b/src-tauri/src/main.rs
index f9eec50..6126e6b 100644
--- a/src-tauri/src/main.rs
+++ b/src-tauri/src/main.rs
@@ -425,6 +425,15 @@ async fn setup_from_file(app: State<'_, App>, request: tauri::ipc::Request<'_>)
     app.sync.setup_from_file(bytes)
 }
 
+/// The theme's `bg` and `text` for the native title bar (Windows 11 only; see `title_bar`).
+#[tauri::command]
+fn set_title_bar_colors(window: tauri::WebviewWindow, bg: String, text: String) {
+    #[cfg(windows)]
+    kestrove_desktop::title_bar::paint(&window, &bg, &text);
+    #[cfg(not(windows))]
+    let _ = (window, bg, text);
+}
+
 #[tauri::command]
 fn clear_setup(app: State<'_, App>) {
     app.sync.clear_setup();
@@ -616,6 +625,7 @@ fn main() {
         })
         .invoke_handler(tauri::generate_handler![
             state,
+            set_title_bar_colors,
             create_account,
             unlock,
             lock,
diff --git a/src-tauri/src/title_bar.rs b/src-tauri/src/title_bar.rs
new file mode 100644
index 0000000..13f4bfb
--- /dev/null
+++ b/src-tauri/src/title_bar.rs
@@ -0,0 +1,52 @@
+//! The window's title bar on Windows and Linux.
+//!
+//! Tauri 2 can only overlay web content on the title bar on macOS (`titleBarStyle: "Overlay"`), so Windows and
+//! Linux keep the native title bar and its window controls. On Windows 11 its caption is painted in the theme's
+//! `bg` with `text` for the title, so it reads as one bar with the app's own header below it. Windows 10 and
+//! Linux (GTK) draw their own colours.
+
+/// `#rrggbb` (a design token) → a Win32 `COLORREF` (`0x00bbggrr`).
+pub fn colorref(hex: &str) -> Option<u32> {
+    let hex = hex.trim().strip_prefix('#')?;
+    if hex.len() != 6 || !hex.bytes().all(|b| b.is_ascii_hexdigit()) {
+        return None;
+    }
+    let rgb = u32::from_str_radix(hex, 16).ok()?;
+    let (r, g, b) = (rgb >> 16, (rgb >> 8) & 0xff, rgb & 0xff);
+    Some(b << 16 | g << 8 | r)
+}
+
+/// Paints the caption, its title and the window border. Errors (Windows 10 has no caption colour) are ignored.
+#[cfg(windows)]
+pub fn paint(window: &tauri::WebviewWindow, bg: &str, text: &str) {
+    use windows_sys::Win32::Graphics::Dwm::{
+        DwmSetWindowAttribute, DWMWA_BORDER_COLOR, DWMWA_CAPTION_COLOR, DWMWA_TEXT_COLOR,
+    };
+    let (Ok(hwnd), Some(bg), Some(text)) = (window.hwnd(), colorref(bg), colorref(text)) else { return };
+    for (attribute, color) in [(DWMWA_CAPTION_COLOR, bg), (DWMWA_BORDER_COLOR, bg), (DWMWA_TEXT_COLOR, text)] {
+        // SAFETY: a live window handle and a COLORREF-sized value, as DwmSetWindowAttribute expects.
+        unsafe {
+            DwmSetWindowAttribute(hwnd.0, attribute as u32, (&color as *const u32).cast(), size_of::<u32>() as u32);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::colorref;
+
+    #[test]
+    fn token_hex_to_colorref() {
+        assert_eq!(colorref("#f4f6f4"), Some(0x00f4f6f4));
+        assert_eq!(colorref(" #0B1210 "), Some(0x0010120b));
+        assert_eq!(colorref("#13201b"), Some(0x001b2013));
+    }
+
+    #[test]
+    fn rejects_other_formats() {
+        assert_eq!(colorref("f4f6f4"), None);
+        assert_eq!(colorref("#fff"), None);
+        assert_eq!(colorref("rgb(1, 2, 3)"), None);
+        assert_eq!(colorref("#gg0000"), None);
+    }
+}
diff --git a/src/main.ts b/src/main.ts
index 18b4cfd..4a39d90 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -81,8 +81,22 @@ function applyTheme(t: Theme) {
   else document.documentElement.dataset.theme = t;
   // The native title bar and window controls follow too.
   void getCurrentWindow().setTheme(t === "system" ? null : t).catch(() => undefined);
+  paintTitleBar();
 }
 
+/// Windows and Linux keep the native title bar (Tauri overlays it only on macOS); on Windows 11 its caption
+/// takes the theme's `bg` and `text`, so it and the header below read as one custom title bar.
+function paintTitleBar() {
+  if (isMac) return;
+  const css = getComputedStyle(document.documentElement);
+  const bg = css.getPropertyValue("--bg").trim();
+  const text = css.getPropertyValue("--text").trim();
+  void invoke("set_title_bar_colors", { bg, text }).catch(() => undefined);
+}
+
+// "System" follows the OS setting while the app runs.
+matchMedia("(prefers-color-scheme: dark)").addEventListener("change", paintTitleBar);
+
 function setTheme(t: Theme) {
   try {
     localStorage.setItem("theme", t);