.home-page-grid-promo {
    width: 100%;
}
.home-page-grid-promo img {
    min-width: 100%;
}
@media (min-width: 769px) {
    .home-page-grid-promo {
        float: left;
        width: calc(50% - 10px);
        margin-bottom: 20px;
    }
    .home-page-grid-promo:nth-child(odd of .home-page-grid-promo) {
        margin-right: 20px;
    }
}