diff --git a/apps/readest-app/src/app/reader/utils/iframeEventHandlers.ts b/apps/readest-app/src/app/reader/utils/iframeEventHandlers.ts
index dbb635c1..916aa8a8 100644
--- a/apps/readest-app/src/app/reader/utils/iframeEventHandlers.ts
+++ b/apps/readest-app/src/app/reader/utils/iframeEventHandlers.ts
@@ -42,6 +42,10 @@ export const handleKeydown = (bookKey: string, event: KeyboardEvent) => {
   if (['Backspace'].includes(event.key)) {
     event.preventDefault();
   }
+  if (event.ctrlKey && event.key.toLowerCase() === 'f') {
+    event.preventDefault();
+  }
+
   window.postMessage(
     {
       type: 'iframe-keydown',
diff --git a/apps/readest-app/src/hooks/useShortcuts.ts b/apps/readest-app/src/hooks/useShortcuts.ts
index 00c943d2..d35ab5f0 100644
--- a/apps/readest-app/src/hooks/useShortcuts.ts
+++ b/apps/readest-app/src/hooks/useShortcuts.ts
@@ -99,6 +99,10 @@ const useShortcuts = (actions: KeyActionHandlers, dependencies: React.Dependency
         return;
       }
 
+      if (ctrlKey && key.toLowerCase() === 'f') {
+        event.preventDefault();
+      }
+
       const handled = processKeyEvent(key.toLowerCase(), ctrlKey, altKey, metaKey, shiftKey, event);
       // console.log('Key event handled:', key, handled);
       if (handled) event.preventDefault();