body{margin: 0;padding: 0;background-color:#f4f4f4}
.content{position: fixed;left: 50%;top: 50%;transform: translate(-50%,-50%);-webkit-transform: translate(-50%,-50%)}
.top{position: absolute;top: 0;left: 0;height: 15px;width: 100%;background: url(../images/top_bg.png) repeat-x;}
.foot{position: absolute;bottom: 0;left: 0;height: 5px;width: 100%;background: url(../images/top_bg.png) repeat-x;}