#fstt-btn{position:fixed;z-index:99999;width:54px;height:54px;border:none;border-radius:50%;display:flex;align-items:center;justify-content:center;box-shadow:0 4px 16px rgb(0 0 0 / .15);cursor:pointer;opacity:.8;transition:opacity 0.3s,transform 0.2s}#fstt-btn:hover{opacity:1;transform:scale(1.07)}.fstt-left-bottom{left:22px;bottom:22px}.fstt-center-bottom{left:50%;bottom:22px;transform:translateX(-50%)}.fstt-right-bottom{right:22px;bottom:22px}.fstt-left-top{left:22px;top:22px}.fstt-center-top{left:50%;top:22px;transform:translateX(-50%)}.fstt-right-top{right:22px;top:22px}@media (max-width:768px){#fstt-btn{width:44px;height:44px}.fstt-left-bottom,.fstt-left-top{left:12px}.fstt-right-bottom,.fstt-right-top{right:12px}.fstt-center-bottom,.fstt-center-top{left:50%}}