chromium/third_party/blink/web_tests/external/wpt/css/css-position/sticky/position-sticky-child-multicolumn-ref.html

<!DOCTYPE html>
<title>Reference for multicolumn under position:sticky should be positioned correctly</title>
<style>
  body {
    margin: 0;
  }
  #scroller {
    overflow-y: scroll;
    width: 200px;
    height: 200px;
  }
  #relative {
    position: relative;
    top: 100px;
    margin: 10px;
  }
  #child {
    width: 100px;
    height: 100px;
    background: green;
  }
  #contents {
    position: relative;
    top: 10%;
    left: 10%;
    width: 80%;
    height: 80%;
    background: lightgreen;
  }
  #spacer {
    height: 400px;
  }
</style>

<div id="scroller">
  <div id="relative">
    <div id="child">
      <div id="contents"></div>
    </div>
  </div>
  <div id="spacer"></div>
</div>

<div>You should see a light green box above with a dark green border, no blue should be visible.</div>

<script>
  window.addEventListener('load', function() {
    scroller.scrollTop = 100;
  });
</script>