#back {
 position: absolute;
 height: 100%;
 width: 100%;
 border: none;
 z-index: 0;
}

#transparent {
 position: absolute;
 height: 100%;
 width: 100%;
 border: none;
 z-index: auto;
 }

#front { 
 position: absolute;
 top:24%; 
 left:33%;
 height:52%; 
 width: 33%; 
 background: teal;
 color: #fff;
 float:left;
 z-index:auto;
 }
 
 body{margin: 0; padding: 0; height:100%;}