.logo {
    background: url('../img/jumis.png') no-repeat 0 50%;
    background-image: none, url('../img/jumis.svg');
}

@media only screen and (max-width: 840px) {
    .logo {
        margin: 0;
        width: 83px;
        height: 25px;
        background-size: 83px auto;
    }
}