.arrow-btn{position:fixed;bottom:20px;right:20px;width:50px;height:50px;background-color:red;color:#fff;border:none;border-radius:50%;display:flex;justify-content:center;align-items:center;cursor:pointer;font-size:24px;opacity:.8;transition:opacity .3s}.arrow-btn:hover{opacity:1}.arrow-btn:before{content:"\2191"}