#back-top{position:fixed;bottom:10px;margin-left:20px;z-index:9990;_position:absolute;_top:expression(documentElement.scrollTop+body.scrollTop);_margin-top:500px}body{_background:url(null) fixed}#back-top a{width:50px;display:block;text-align:center;font:11px/100% Arial,Helvetica,sans-serif;text-transform:uppercase;text-decoration:none;color:#bbb;-webkit-transition:1s;-moz-transition:1s;transition:1s}#back-top a:hover{color:#000}#back-top span.icon{width:50px;height:50px;display:block;margin-bottom:7px;background:#ddd url(up-arrow.png) no-repeat center center;-webkit-border-radius:8px;-moz-border-radius:8px;border-radius:8px;-webkit-transition:1s;-moz-transition:1s;transition:1s}#back-top a:hover span{}