Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/external/wpt/css/css-scrollbars/transparent-on-root-ref.html 

<!doctype html>
<meta charset="utf-8">
<title>CSS Test: non-opaque scrollbar-color should work on the root</title>
<style>
:root {
  background-color: black;
}
</style>