diff --git a/source/less/_article.less b/source/less/_article.less
index 514417b..b214cd9 100755
--- a/source/less/_article.less
+++ b/source/less/_article.less
@@ -415,6 +415,7 @@
       vertical-align: top;
       border: 0px solid darken(@theme_bg_main, 2%);
       &:before{
+          content: "";
           position: absolute;
           top: 0;
           right: 0;
@@ -458,6 +459,9 @@
   &.python .code:before{
       content: "python";
   }
+  &.plain .code:before{
+      content: "";
+  }
 
   &::-webkit-scrollbar {
     height: @border_radius_code_block;