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

@media screen and (max-height: 600px){
	#lightbox{
		margin:40px auto 40px;
	}
}
@media screen and (min-height: 900px){
	#lightbox{
		margin:160px auto 100px;
	}
}