nav a:first-child{
	border-bottom: 2px solid white;
}
.introduce{
	height: 800px;
	margin-top: 40px;
}
.introduce div{
	width: 770px;
	margin: 0 auto;
	text-indent: 2em;
	line-height: 30px;
	color: white;
}
.introduce img{
	display: block;
	width: 770px;
	margin: 0 auto;
	margin-top: 10px;
}
/*.introduce div{
	float: left;
	width: 406px;
	height: 180px;
	margin: 50px 30px 0 0;
}
.introduce div span{
	display: inline-block;
	width: 200px;
	height: 180px;
	text-align: center;
	line-height: 180px;
	font-size: 50px;
	background-color: white;
	border: 3px solid #F5C201;
	color: #F5C201;
}
.introduce div img{
	float: right;
	width: 200px;
	height: 186px;
	background-color: white;
}*/