#back-top a,#back-top span{width:1px;height:1px;display:block}#back-top{position:fixed;bottom:130px;right:20px}#back-top a{background:url(../img/index_top/pagetop.png) no-repeat}#back-top a:hover{background-position:0 bottom}#back-top span{margin-bottom:7px;left:auto;margin-right:auto}