.back-to-top{position:fixed;right:20px;width:50px;height:50px;background-color:#178751;border-radius:4px;cursor:pointer;transition:background-color .3s,bottom .3s ease;z-index:999;scroll-behavior:smooth}.back-to-top:hover{background-color:#306149}.back-to-top::before{content:"";border:solid #fff;border-width:0 4px 4px 0;display:inline-block;padding:8px;transform:rotate(-135deg);top:20px;left:14px;position:relative}