LayoutTests/compositing/backgrounds/negative-z-index-behind-body.html - WebKit - Git at Google

 <style>
 body {
     position: relative;
     background: white;
 }

 div {
     position: absolute;
     z-index: -1;
     transform: translateZ(0);
 }

 .green {
     background-color: green;
     width: 200px;
     height: 200px;
 }
 </style>
 <body>
 <div class="green"></div>
 <div></div>
	<style>
	body {
	position: relative;
	background: white;
	}

	div {
	position: absolute;
	z-index: -1;
	transform: translateZ(0);
	}

	.green {
	background-color: green;
	width: 200px;
	height: 200px;
	}
	</style>
	<body>
	<div class="green"></div>
	<div></div>