body {
 	background: #FFFFFF url(../img/fondo.gif) repeat-x top left;
	margin: 0;
  padding: 0;
	height: 100%;
	text-align: center;
}

 #centered
      {
      position: absolute;
      left: 50%;
      top: 50%;
      width: 750px;
      height: 600px;
      margin-left: -375px; /* half of width */
      margin-top: -300px;  /* half of height */
      }