css/css-transforms/backface-visibility-hidden-003.html

<!DOCTYPE html>
<title>backface visibility: hidden creates containing block and stacking context when participating in a 3D rendering context</title>
<link rel="author" title="Matt Woodrow" href="mailto:mattwoodrow@apple.com">
<link rel="help" href="http://www.w3.org/TR/css-transforms-1/#transform-property">
<link rel="help" href="http://www.w3.org/TR/css-transforms-2/#propdef-backface-visibility">
<link rel="match" href="backface-visibility-hidden-003-ref.html">

<p>The test passes if there is a green rectangle and no red.</p>
<style>
.outer {
  transform-style: preserve-3d;
  width: 100px;
  height: 100px;
  background-color: red;
}

.inner {
  backface-visibility: hidden;
}

.positioned {
  position: absolute;
  top: -100px;
  z-index: -1;
  width: 100px;
  height: 100px;
  background-color: green;
}

.sibling {
  width: 100px;
  height: 100px;
  background-color: blue;
}

</style>

<div class="outer">
  <div class="sibling"></div>
  <div class="inner">
    <div class="positioned"></div>
  </div>
</div>