#back-top a {
    position: fixed;
    bottom: 20px;
    right: 25px;
    background-color: var(--primary, var(--first-nav-back));
    opacity: .7;
    width: 55px;
    height: 55px;
    text-align: center;
    font-size: 25px;
    z-index: 100;
    color: rgba(255, 255, 255, .7);
    box-shadow: 0 2px 6px -1px rgba(0, 0, 0, .16), 0 6px 18px -1px rgba(0, 0, 0, .1) !important;
    transition: all .5s ease-in-out;
}

#back-top a:hover {
    color: rgba(255, 255, 255, 1);
    background-color: var(--primary, var(--first-nav-back));
    opacity: 1;
}

#back-top i {
    font-size: 35px;
    padding-top: 8px;
}