Add Different Mobile Logo (CSS)

/* Add custom mobile logo */
@media only screen and (max-width: 1000px) {
    body header#top #logo img {
        visibility:hidden !important;
    }
    body header#top #logo:before {
        content: '';
        position: absolute;
        width: 100%;
        height: 100%;
        background: url(http://yoursite.co/wp-content/uploads/2017/05/Logo.png) no-repeat;
        background-size: 50px;
    }
}