.to-top-button {
    position: fixed;
    bottom: 15px;
    right: 15px;
    z-index: 99;
    cursor: pointer;
    padding: 15px;
    background-color: transparent;
    height: 55px;
    width: 55px;
    padding:0px;
    opacity: 0;
}

@media screen and (max-width: 768px) {
    .to-top-button {
        position: fixed;
        bottom: 15px;
        right: 5px;
        z-index: 99;
        cursor: pointer;
        padding: 15px;
        background-color: transparent;
        height: 55px;
        width: 55px;
        padding:0px;
        opacity: 0;
    }
}