@media screen and (max-width: 39.99em) {
    #sidebar #menuHeader #logo a {
        background-image: url('/content/portalspecific/localhost/logo-small.png');
    }
}

@media screen and (min-width:40em) {
    #sidebar #menuHeader #logo a {
        background-image: url('/content/portalspecific/localhost/logo.png');
    }
}