<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
	"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
	<title></title>
	<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<style type="text/css">


#stackA {
	opacity: 0.66; 
	z-index: 2; 
	background: red; 
	width: 300px; 
	height: 300px;
	}

#stackB {
	opacity: 0.90; 
	background: blue; 
	margin-top: -150px; 
	width: 150px; 
	height: 300px;
	}

</style>
</head>

<body>
	<div id="stackA"></div>

	<div id="stackB"></div>
</body>
</html>