修复移动端菜单显示bug

Author: qiesun

_includes/left_directory.html

@@ -73,7 +73,7 @@
       position: fixed;
       top: 0;
       right: 100%;
-      z-index: 10;
+      z-index: 11;
       width: 100%;
       height: 100%;
       margin: 0;