html {
	height: 100%;
}
body {
	margin: 0;
	padding: 0;
	height: 100%;
}
#enter {
	margin:0 auto; 
	text-align:center; 
	vertical-align:middle; 
	position:absolute; 
	top:30%; 
	left:30%; 
	width:40%; 
	height:40%
}