#center{
	width: 100%;
	height: 320px;
	margin: 20px auto;
	margin-bottom: 50px;
}
.center_div{
	overflow: hidden;
	width: 80%;
	margin: 0px auto;
	height: 420px;
	background-color: rgb(239, 239, 239);
	border-radius: 5px;
}
.center_div li{
	width: 90%;
	line-height: 40px;
	list-style: none;
	height: 40px;
	margin: 10px auto;
}