.back-to-top {
    position: fixed;
    bottom: 20px;
    cursor: pointer;
    padding: 10px 15px;
    border-radius: 5px;
    font-size: 18px;
    display: none;
    z-index: 9999;
}

.back-to-top[data-position="right"] {
    right: 20px;
}

.back-to-top[data-position="left"] {
    left: 20px;
}