#backToTop {
    position: fixed;
    right: 25px;
    bottom: 25px;
    z-index: 1050;

    width: 48px;
    height: 48px;
    padding: 0;

    display: none;
    align-items: center;
    justify-content: center;

    border-radius: 50%;
    cursor: pointer;
}

#backToTop.show {
    display: flex;
}