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chromium/third_party/blink/web_tests/paint/stacking/html-with-negative-z-index.html 

<!doctype html>
<style>
* {
  margin: 0;
}
html {
  background: white;
  width: 200px;
  height: 200px;
  position: relative;
  z-index: -1;
}
.compDesc {
  will-change: transform;
  position: absolute;
  top: 0;
  left: 50px;
  width: 50px;
  height: 100px;
  background: green;
  z-index: -2;
}
.desc {
  width: 50px;
  height: 100px;
  background: green;
}
</style>
<div class="compDesc"></div>
<div class="desc"></div>