.banner {
	height: 202px;
	background: url(http://www.boygjj.com/images/quanwfab_banner1228.jpg) center center no-repeat;
	min-width: 1200px;
}

@media screen and (max-width:768px) {
	.banner {
		height: 200px;
		background: url(http://www.boygjj.com/images/qwfbyd1228.jpg) center center no-repeat;
		min-width: auto;
	}
}