message: Update background color for classnames demo
diff: @@ -63,6 +63,7 @@ html[data-theme='dark'] .header-github-link:before {
  }
  .ruleGroup {
  + background-color: #00000011;
  border: 2px solid maroon;
  padding: $structure-padding;
  row-gap: $structure-padding !important;
  