.scroll-to-top-btn{display:flex;justify-content:center;align-items:center;position:fixed;right:20px;bottom:10%;z-index:20;opacity:0;border:1px solid #1a1a1a;border-radius:100%;background-color:#1a1a1a;height:44px;width:44px;transition:opacity .25s}.scroll-to-top-btn.active{opacity:1;transition:opacity .25s}