CSSStyleSheet-constructable-concat-ref.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Adoptedstylesheets.concat should work when starting empty</title>
<link rel="author" href="mailto:[email protected]">

<span>This should be green</span><br>
<span>This should be green</span>
<pre>Tests:
PASS
PASS
PASS
PASS
</pre>

<style>
  span {
    background-color:green;
  }
</style>

chromium/third_party/blink/web_tests/external/wpt/css/cssom/CSSStyleSheet-constructable-concat-ref.html