.tyh-back-top{position:fixed;width:40px;height:40px;background:#fff;box-shadow:0 2px 12px #0003;border-radius:50%;user-select:none;cursor:pointer;display:flex;justify-content:center;align-items:center;color:#484848;font-size:14px;z-index:999999}.tyh-back-top:hover{transition:background .2s;background:rgb(244,248,253)}