html {
	text-align: center;
	margin: 0px;
	padding: 0px;
	display: block;
}
body {
	margin: 0px auto;
	padding: 0px;
	text-align: left;
	background-color: #F8F8F8;
	
}
#kuangjia{
height:100%;
width:100%;
z-index:1;
}
.down_ding{
	bottom: 20px;
	position: absolute;
	overflow: hidden;
}#sidebar {
	z-index: 2;
}