body{
    font-family: Arial;
	text-align:center;
}

header{
    position: fixed;
    width: 100%;
    z-index: 20;
}
#main{
	position: absolute;
	width:700px;
	top: 50%;
	left: 50%;
	margin-top: -200px;
	margin-left: -350px;
}