:root {
    --content-width: 1140px;
}

.page-up {
    position: fixed;
    bottom: 10px;
    right: 10px;
    z-index: -1;
    display: block;
    width: 34px;
    height: 42px;
    background-color: rgb(17, 17, 17);
    color: #fff;
    text-align: center;
    font-size: 12px;
    line-height: 42px;
    opacity: 0;
    transition: all .3s linear;
    font-weight: 800;
    cursor: pointer;
}

.page-up:hover {
    background-color: rgba(17, 17, 17, 0.6);
}

.page-up.show {
    opacity: 1;
    z-index: 99999;
}