<!DOCTYPE HTML>
<html>
<head>
<style>
#d1 {
overflow:hidden;
height:0;
}
#d2 {
opacity:0.50196078431;
#d3 {
position:absolute;
left:0;
top:0;
width:100%;
height:100%;
background:blue;
</style>
</head>
<body>
<div id="d1">
<div id="d2">
<div id="d3"></div>
</div>
</body>
</html>