div#page {
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
    padding: 20px;
}

.back-to-top {
    position: fixed;
    font-size: 15pt;
    bottom: var(--BackToTopBottom);
    right: var(--BackToTopRight);
    text-decoration: none;
    color: #fff;
    z-index: 9999;
    display: none;
    padding: 5px;
}

    .back-to-top img {
        border: 0px;
        width: 35px;
        height: 35px;
    }

    .back-to-top:hover {
        color: white;
    }

@media only screen and (max-width : 800px) {
    .back-to-top {
        display: none;
    }

        .back-to-top img {
            display: none;
        }
}