.portfolio_show{ background-image: url(../pic/aboutus/aboutus-bg.jpg); background-repeat:repeat-x; height:280px; margin-bottom:12px;color:#a1a1a1}
.portfolio_show .left{float:left; width:55px; height:280px; background-image:url(../pic/aboutus/aboutus-left.jpg);}
.portfolio_show .right{ float:right; width:56px; height:280px; background-image:url(../pic/aboutus/aboutus-right.jpg);}
.portfolio_show .left img{}
.portfolio_show .right img{ }
.right-o{ margin-top:147px; }

.item {
   margin:0px;padding:0px;float: left; display: inline;width:550px;height:auto;
}