Revert "Merge branch 'fix-sidebar-exapnd' into 'master'"

This reverts merge request !3520

app/assets/stylesheets/framework/sidebar.scss

@@ -200,7 +200,7 @@
   top: 0;
   left: 0;
   font-size: 20px;
-  background: #fff;
+  background: transparent;
   height: 59px;
   text-align: center;
   line-height: 59px;