.hero-unit .hero-image { width: 100%; }

@media (max-width: 767px) {
    .hero-unit .hero-image.desktop-size {
        display: none;
    }
    .hero-unit .hero-image.mobile-size {
        display: block;
    }
}


@media (min-width: 768px) {
    .hero-unit .hero-image.desktop-size {
        display: block;
    }
    .hero-unit .hero-image.mobile-size {
        display: none;
    }
}