diff --git a/src/components/PageTitleContext.tsx b/src/components/PageTitleContext.tsx
index 53e15ab..b7ed6c6 100644
--- a/src/components/PageTitleContext.tsx
+++ b/src/components/PageTitleContext.tsx
@@ -1,7 +1,7 @@
 import {
   createContext,
   useContext,
-  useEffect,
+  useLayoutEffect,
   useState,
   type PropsWithChildren,
 } from "react";
@@ -31,10 +31,16 @@ export function usePageTitle(): string | null {
   return useContext(PageTitleContext)?.title ?? null;
 }
 
-/** Publish the current page's title; clears it again when the page unmounts. */
+/**
+ * Publish the current page's title; clears it again when the page unmounts.
+ * Uses useLayoutEffect so the title updates synchronously with the page render
+ * — otherwise switching language (e.g. cn -> ms) showed the previous title for
+ * one paint while the post-commit useEffect was still pending, which read as a
+ * flicker in the header.
+ */
 export function useSetPageTitle(title: string | null): void {
   const setTitle = useContext(PageTitleContext)?.setTitle;
-  useEffect(() => {
+  useLayoutEffect(() => {
     setTitle?.(title);
     return () => setTitle?.(null);
   }, [setTitle, title]);