.article{height:2700px}


.article .art_cont{width:910px; height:2800px; background:url("/image/art13.jpg") no-repeat;padding-top:1900px;}

.article .art_cont>div{width:448px; height:224px;float:left;margin:5px 5px 0 0;position:relative; cursor:pointer;}
.article .art_cont>div img{position:absolute; top:0; left:0}

.article .art_cont>div .on3{display:none;}