diff --git a/src/main.py b/src/main.py
index 00cfbd6..7a7c34b 100644
--- a/src/main.py
+++ b/src/main.py
@@ -265,9 +265,32 @@ async def list_projects_compat():
 
 
 # ---------------------------------------------------------------------------
-# 静态文件服务（前端 dist/，F18 实现）
+# 靜態文件服務（前端 dist/，F18 實現）
 # ---------------------------------------------------------------------------
 
 DIST_DIR = Path(__file__).parent / "frontend" / "dist"
 if DIST_DIR.exists():
-    app.mount("/", StaticFiles(directory=str(DIST_DIR), html=True), name="frontend")
+    # v3.1: 緩存策略 - HTML 不緩存（確保新版本生效），JS/CSS 長緩存（Vite content hash 已處理）
+    import mimetypes
+    _static_app = StaticFiles(directory=str(DIST_DIR), html=True)
+    
+    class CachedStaticFiles:
+        """包裝 StaticFiles，添加 Cache-Control 頭"""
+        def __init__(self, app):
+            self._app = app
+        
+        async def __call__(self, scope, receive, send):
+            original_send = send
+            async def patched_send(message):
+                if message.get("type") == "http.response.start":
+                    headers = dict(message.get("headers", []))
+                    path = scope.get("path", "")
+                    if path.endswith(".html") or path == "/":
+                        headers[b"cache-control"] = b"no-cache, no-store, must-revalidate"
+                    elif any(path.endswith(ext) for ext in (".js", ".css", ".woff2", ".png", ".ico")):
+                        headers[b"cache-control"] = b"public, max-age=31536000, immutable"
+                    message["headers"] = list(headers.items())
+                await original_send(message)
+            await self._app(scope, receive, patched_send)
+    
+    app.mount("/", CachedStaticFiles(_static_app), name="frontend")