diff --git a/site/theme/static/demo.less b/site/theme/static/demo.less
index 3e51f47949..918f9432cc 100644
--- a/site/theme/static/demo.less
+++ b/site/theme/static/demo.less
@@ -165,6 +165,7 @@ section.code-box-meta p {
   opacity: 0;
   overflow: auto;
   transition: all 0.4s ease;
+  border-radius: 0 0 6px 6px;
 }
 .code-box .highlight-wrapper-expand {
   max-height: 500px;
@@ -175,6 +176,7 @@ section.code-box-meta p {
   pre {
     margin: 0;
     padding: 0;
+    background: #fff;
   }
   &:not(:first-child) {
      border-top: 1px dashed #e9e9e9;