.jump-top-box{width:50px;position:fixed;z-index:999;top:-1000px}.jump-top-box .jump-top{width:50px;height:50px;position:relative;z-index:1}.jump-top-box .jump-top a{display:block;width:50px;height:50px;background:#73d661 url(//exp.bdstatic.com/static/common-jquery/widget/js/ui/jump-top/img/top_752a2dc.png?__sprite) no-repeat;border-radius:2px}.jump-top-box .jump-top a:hover{background:#9de290 url(//exp.bdstatic.com/static/common-jquery/widget/js/ui/jump-top/img/top-hover_3a1dfd4.png?__sprite) no-repeat}