.sponsor {
    width: 24%;
    display: inline-block;
    vertical-align: middle;
    padding: 20px 30px;
}

@media all and (max-width: 850px) {
    .sponsor {
        width: 35%;
    }
}

@media all and (max-width: 550px) {
    .sponsor {
        width: 50%;
    }
}