diff --git a/backend/main.go b/backend/main.go
index 3d8a34a..1cfce1b 100644
--- a/backend/main.go
+++ b/backend/main.go
@@ -78,10 +78,17 @@ func main() {
 		}
 		if f, err := dist.Open(path); err == nil {
 			f.Close()
+			// 带 hash 的静态资源（assets/*）可长期缓存；index.html 必须每次重新验证
+			if strings.HasPrefix(path, "assets/") {
+				c.Header("Cache-Control", "public, max-age=31536000, immutable")
+			} else {
+				c.Header("Cache-Control", "no-cache")
+			}
 			fileServer.ServeHTTP(c.Writer, c.Request)
 			return
 		}
-		// SPA fallback
+		// SPA fallback — 必须 no-cache，否则浏览器缓存旧 index.html 会白屏
+		c.Header("Cache-Control", "no-cache")
 		c.Request.URL.Path = "/"
 		fileServer.ServeHTTP(c.Writer, c.Request)
 	})