body{
	background:#f1f1f1;
}
.box{
	width:1000px;
	overflow:hidden;
	margin:0 auto;
	background:#fefefe;
	padding:20px;
}
.main-content{
	font-size:15px;
	line-height:24px;
}
.f1{
	font-size: 30px;
}
.f2{
	font-size: 22px;
	line-height: 50px;
}
.f3{
	font-size: 20px;
}
.warn{
	font-weight: bold;
	text-decoration:underline;
}
.red{
	color:red;
}