.tab_box {
  overflow: hidden;
}
ul.pic_list{ margin:30px 0;_overflow:hidden;_zoom:1}
ul.pic_list li{ width:253px;}
.content_1_top{ _height:47px;*height:47px;}
.content_1_top li{ border: 1px solid #dedede;
 cursor: pointer;
 float: left;
 font-size: 16px;
 height: 45px;
 line-height: 45px;
 margin-right: 20px;
 text-align: center;
 width: 180px;}
.content_1_top li.active{ background:#d11307; color:#fff}	

@media only screen and (max-width:768px){
ul.pic_list li{ border:8px solid #fff; width:45%;}	
.content_1_top li{ width:23%; margin-right:2%; box-sizing:border-box}
 
 }
@media only screen and (max-width:640px){
ul.pic_list li{width:80%;}	
 } 
@media only screen and (max-width:375px){
.content_1_top li{ width:46%; margin:0 2%}
.content_1_top li:nth-child(1),.content_1_top li:nth-child(2),.content_1_top li:nth-child(3),.content_1_top li:nth-child(4){ margin-bottom:20px}
 
 }