diff --git a/backend/auth.js b/backend/auth.js
index 1fe9fb6..f363372 100644
--- a/backend/auth.js
+++ b/backend/auth.js
@@ -102,7 +102,9 @@ function authMiddleware(req, res, next) {
       storage_permission: user.storage_permission || 'sftp_only',
       current_storage_type: user.current_storage_type || 'sftp',
       local_storage_quota: user.local_storage_quota || 1073741824,
-      local_storage_used: user.local_storage_used || 0
+      local_storage_used: user.local_storage_used || 0,
+      // 主题偏好
+      theme_preference: user.theme_preference || null
     };
 
     next();