body, html {
        height: 100%;
}

html {
        background: url(../img/logo.png);
        background-position: center;
        background-repeat: no-repeat;
        background-size: cover;
}

@media screen and (max-aspect-ratio: 4/3) {
        html {
                background: url(../img/logo-vertical.png);
                background-position: center;
                background-repeat: no-repeat;
                background-size: cover;
        }
}