#goTopBtn {
    position: fixed;
    line-height: 46px;
    text-align: center;
    width: 46px;
    bottom: 35px;
    height: 46px;
    cursor: pointer;
    background: #fff;
    display: none;
    border-radius: 6px;
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.13);
    font-size: 22px;
    color: #999;
}