Merge pull request #185 from xyzget/patch-1

修正全屏之后背景内容重叠的问题

scss/editormd.codemirror.scss

@@ -18,6 +18,7 @@
     line-height: 1.6;
     display: none;
     background: #fff;
+    z-index:10;
 }
 
 .editormd {
@@ -86,4 +87,4 @@
         background-position: right;
         background-repeat: no-repeat;
     }
-}
+}