#content {padding-bottom: 15px}

.sub-div {margin: 10px 0 20px}

#gallery {
    display: grid;
    column-gap: 15px;
    row-gap: 10px;
    padding: 0 15px;

    img {width: 100%}
}

@media only screen and (min-width:700px) {
    #gallery {
        grid-template-columns: 1fr 1fr 1fr;
        max-width: 1400px;
        margin: 0 auto 30px;
    }
}

@media only screen and (max-width:700px) {#gallery {grid-template-columns: 1fr 1fr;}}