diff --git a/frontend/src/lib/components/reader/foliate-view.svelte b/frontend/src/lib/components/reader/foliate-view.svelte
index ef122d8..e247fce 100644
--- a/frontend/src/lib/components/reader/foliate-view.svelte
+++ b/frontend/src/lib/components/reader/foliate-view.svelte
@@ -104,7 +104,46 @@
 		doc.addEventListener('keydown', onKeydown);
 	}
 
+	/**
+	 * Replays a shortcut pressed inside the book on the host window.
+	 *
+	 * Key events do not cross document boundaries, so a shortcut pressed while
+	 * the book has focus never reaches the app's handlers — which are bound on
+	 * the window, as the sidebar's ctrl+B is — and the browser's own default runs
+	 * instead. That is why ctrl+B opened bookmarks in the book but toggled the
+	 * chapter sidebar everywhere else.
+	 *
+	 * The original is only cancelled if an app handler actually claimed the
+	 * replay, so combinations the app does not use — ctrl+C above all — keep
+	 * their normal browser behaviour.
+	 */
+	function forwardShortcut(event: KeyboardEvent) {
+		const source = (event.target as Node | null)?.ownerDocument;
+		// isTrusted rules out the replay itself, which would otherwise recurse.
+		if (!event.isTrusted || !source || source === document) return;
+
+		const claimed = !window.dispatchEvent(
+			new KeyboardEvent('keydown', {
+				key: event.key,
+				code: event.code,
+				ctrlKey: event.ctrlKey,
+				metaKey: event.metaKey,
+				shiftKey: event.shiftKey,
+				altKey: event.altKey,
+				bubbles: true,
+				cancelable: true
+			})
+		);
+
+		if (claimed) event.preventDefault();
+	}
+
 	function onKeydown(event: KeyboardEvent) {
+		if (event.ctrlKey || event.metaKey || event.altKey) {
+			forwardShortcut(event);
+			return;
+		}
+
 		switch (event.key) {
 			case 'ArrowLeft':
 			case 'PageUp':