.center {
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -100px;
  margin-left: -100px;
}

html {
	background: #52473b url(background.jpg) no-repeat center center fixed;
	-webkit-background-size: cover;
	-moz-background-size: cover;
	-o-background-size: cover;
	background-size: cover;
}