ul.bn_area{
	width:635px;
	margin: 40px auto 60px;
	overflow:hidden;
}

ul.bn_area li{
	float:left;
	width:197px;
	margin:10px 20px 0 0;
}

ul.bn_area li:nth-child(3n){
	margin:10px 0 0 0;
}


@media (max-width: 640px) {

ul.bn_area{
	width:90%;
	margin: 20px auto 60px;
}
ul.bn_area li{
	width:49%;
}
ul.bn_area li img{
	width:100%;
}
ul.bn_area li{
	margin:10px 2% 0 0;
}
ul.bn_area li:nth-child(3n){
	margin:10px 2% 0 0;
}
ul.bn_area li:nth-child(2n){
	margin:10px 0 0 0!important;
}
}