.reference-gallery {
    margin-top: 25px;
}

.reference-gallery__item,
.reference-gallery__item:visited {
    display: inline-block;
    width: 70px;
    margin: 0 3px 3px 0;
}

.reference-gallery__img {
    width: 100%;
    padding-bottom: 90%;
    background-size: cover;
    background-position: center;
}

@media (min-width: 600px) {
    .reference-gallery {
        margin-top: 30px;
    }

    .reference-gallery__item,
    .reference-gallery__item:visited {
        width: 100px;
         margin: 0 10px 10px 0;
    }
}

@media (min-width: 1600px) {
    .reference-gallery {
        margin-top: 50px;
        margin-bottom: 50px;
    }
    
    .reference-gallery__item,
    .reference-gallery__item:visited {
        width: 150px;
         margin: 0 10px 10px 0;
    }
}