.clearfloat:after{display:block;clear:both;content:"";visibility:hidden;height:0;} 
.clearfloat{zoom:1;}
.pic_lsit li{
   width:25%;
   margin-bottom:30px;
   height:280px;
   text-align:center;
   float:left;
   margin:0px 16px 0px 20px;}
.pic_lsit li a{
   display:block;
   width:90%;
   height:280px;
   margin:0 auto;}
.pic_lsit li a img{
   width:100%;
   height:240px;}
.pic_lsit li a .sm{
  height:40px;
  line-height:40px;
  font-size:16px;
  color:#333;}