/* CSS Document */
body {
	background-image: url(background.png);
	font-family: sans-serif, Verdana, Arial;
}
.kasten {
	width: 420px;
	position: absolute;
	left: 50%;
	margin-left: -210px;
	margin-top: 0px;
	
	text-align: center;
}
.ref {
	float: left;
	width: 150px;
	padding: 20px;
	text-align: center;
	background-color: rgb(219,219,219);
	margin:10px;
}

.ref:hover {
  background-color: rgb(171,171,171);
}