body {
	background-color: rgb(242, 249, 251);
              text-align:center;
}
div.header {
	width: 100%;
}
div.main {
	width: 635px; margin-right: auto; margin-left: auto;
}
div.sub_lh {
	width: 180px; height: 350px; float: left;
}
div.sub_center {
	width: 320px; height: 350px; float: left;
}
div.sub_rh {
	width: 135px; height: 350px; float: left;
}
div.footer {
	width: 770px; clear: both; margin-right: auto; margin-left: auto;
}