position:absolute & determinate z-index
by roskoshinsky
HTML
<div class="owner" >
<div class="box red" ></div>
<div class="box blue" ></div>
<div class="box green" ></div>
</div>
CSS
* {box-sizing:border-box; -moz-box-sizing:border-box; -webkit-box-sizing:border-box;}
div {border:5px solid yellow;}
body{margin:0px; padding:0px;}
.owner {position:absolute; top:0px; left:0px; width:100%; height:100%; z-index:1}
.box {position:absolute; width:100px; height:100px;}
.red {top:20px; left:20px; background-color:red;}
.blue {top:60px; left:60px; background-color:blue; z-index:100;}
.green {top:100px; left:100px; background-color:green;}
.yellow {top:50px; left:50px; background-color:yellow; z-index:2;}