*{ margin:0; padding:0; list-style:none;}
.bg{ width:100%; max-width:640px; min-width:320px; margin:0 auto}
.top,.foot{ width:100%; height:60px; background:#F66;}
.foot{ margin-top:10px;}
.main{ width:100%; overflow:hidden}
.main li{ width:48%; float:left; height:100px; background:#ececec; margin-top:10px; margin-left:1%; margin-right:1%;}