#back-to-top{display:none;position:fixed;bottom:20px;right:30px;z-index:99;border:0;outline:0;background-color:#f1c40f;color:#333;cursor:pointer;padding:15px;border-radius:50%;font-size:18px;box-shadow:0 4px 8px rgba(0,0,0,.2);transition:background-color .3s,transform .3s;width:50px;height:50px;display:flex;align-items:center;justify-content:center;opacity:0;visibility:hidden}#back-to-top.show{display:flex;opacity:1;visibility:visible}#back-to-top:hover{background-color:#d4ac0d;transform:translateY(-3px)}.arrow-up{border:solid #333;border-width:0 3px 3px 0;display:inline-block;padding:5px;transform:rotate(-135deg);-webkit-transform:rotate(-135deg);margin-top:5px}