.banner{overflow:hidden;position:relative}.banner .img{height:2000px;position:absolute;left:0;top:0}.banner .img li{margin-bottom:-8px}.banner .img li a:hover img{opacity:.7;filter:alpha(opacity=70)}.banner .img li a div{width:140px;height:25px;text-align:center;color:#333;font-family:"微软雅黑";font-size:12px;font-weight:bolder;background-color:#fff;opacity:.5;line-height:25px;top:-25px;position:relative}.btn{position:absolute;width:50px;height:30px;background:#fff;position:absolute;top:50%;color:#afafaf;margin-top:270px;cursor:pointer;text-align:center;line-height:30px;color:#000;font-family:"宋体";display:none}.btn:hover{color:#080808}.btn li{color:#afafaf}.btn li:hover{color:#767676}.banner:hover .btn{display:block}.btn_l{left:10px}.btn_r{left:80px}