#return-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0, 0, 0, 0.7);
    width: 50px;
    height: 50px;
    text-decoration: none;
    border-radius: 35px;
    display: none;
    transition: all 0.3s ease;
}

    #return-to-top i {
        color: #fff;
        margin: 0;
        position: relative;
        left: 16px;
        top: 13px;
        font-size: 19px;
        transition: all 0.3s ease;
    }

    #return-to-top:hover {
        background: rgba(0, 0, 0, 0.9);
    }

        #return-to-top:hover i {
            color: #fff;
            top: 5px;
        }