chromium/third_party/blink/web_tests/css3/blending/isolation-isolate-simple.html

<!DOCTYPE HTML>
<style>
.red {
  position: absolute;
  width: 100px;
  height: 200px;
  background-color: red;
  z-index: 0;
}
.green {
  width: 100px;
  height: 100px;
  background-color: green;
  z-index: -1;
}
.isolate {
  width: 100px;
  height: 100px;
  isolation: isolate;
}
.layer {
  transform: translateZ(0);
}
</style>

<div class="red"></div>
<div class="isolate">
  <div class="green"></div>
</div>
<div class="isolate layer">
  <div class="green"></div>
</div>