chromium/third_party/blink/web_tests/external/wpt/css/css-contain/contain-style-counters-004.html

<!DOCTYPE html>
<meta charset="UTF-8">
<title>CSS Containment Test: 'contain: style' for counters (span descendants of &lt;body&gt;)</title>
<link rel="author" title="GĂ©rard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
<link rel="help" href="https://www.w3.org/TR/css-contain-1/#containment-style">
<link rel="match" href="reference/contain-style-counters-004-ref.html">
<style>
body {
  counter-reset: counter-of-span 13;
  contain: style;
}
body span {
  counter-increment: counter-of-span 5;
}
div {
  font-size: 3em;
}
div::after {
  content: counter(counter-of-span);
}
</style>
<body>
  <p><span></span> <span></span> <span></span> <span></span></p>

<!-- The <span>s aren't allowed to modify the counter instantiated on the <body>,
       so a new instance of the counter is created.
       Since the <div> isn't a sibling of the <span>, it will not inherit this new instance,
       and instead it will read the original counter from the <body>, with value 13.
       This is per example at: https://drafts.csswg.org/css-contain/#containment-style  -->
  <p>Test passes if there is the number 13.</p>
  <div></div>
</body>