.mainbox{width: 100%;background: url(mainbg.jpg) center top no-repeat;}
.main{width: 1004px;margin: 0 auto;background: #fff;overflow: hidden;border-right:1px solid #999;border-left:1px solid #999;}

#main_left{width: 245px;float: left;margin: 5px;}
#main_right{width: 730px;float: left;}