chromium/third_party/blink/web_tests/external/wpt/css/css-anchor-position/anchor-scroll-overflow-hidden-ref.html

<!DOCTYPE html>
<link rel="stylesheet" href="/fonts/ahem.css">
<style>
body {
  font: 20px/1 Ahem;
  margin: 0;
}

#placefiller-above-anchor {
  height: 200px;
}

#placefiller-before-anchor {
  display: inline-block;
  width: 50px;
}

#inner-anchored {
  color: green;
  position: fixed;
  left: 70px;
  top: 180px;
}

#outer-anchored {
  color: yellow;
  position: fixed;
  left: 70px;
  top: 220px;
}
</style>

<div id="placefiller-above-anchor"></div>
<div id="placefiller-before-anchor"></div>
<span id="anchor">anchor</span>
<div id="inner-anchored">inner-anchored</div>
<div id="outer-anchored">outer-anchored</div>