html { 
  background: url("renge.jpg") no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

.absoluteCenter {
 /* Must manually set width/height */
 width:520px;
 height:610px;

 /* The magic centering code */
 margin:auto;
 position:absolute;
 top:0;bottom:0; /* Aligns Vertically - Remove for Horizontal Only */
 left:0;right:0; /* Aligns Horizontally - Remove for Vertical Only  */

 /* Prevent div from overflowing main window */
 max-width:100%;
 max-height:100%;
 overflow:auto;
}

/* IE 7 and Below */
:first-child+html .absoluteCenter,
* html .absoluteCenter {
 /* Place code here to override all above values, and add IE friendly centering */
}