.button_uptop{cursor:pointer;width:32px;height:32px;overflow:hidden;text-align:center;border:1px solid #6d9fe6;color:#999;border-radius:3px;float:left;position:fixed;right:16px;bottom:15px;z-index:900;display:-webkit-box;display:flex;-webkit-box-align:center;align-items:center;-webkit-box-pack:center;justify-content:center;visibility:hidden}