.gallery, .viewer {
    display:  block;
}

.gallery {
    min-height: 500px;
}

.viewer {
    min-height: 370px;
    text-align: center;
}

.viewer img {
    max-height: 400px;
    margin: .5em auto;
}

.thumbnails {
    display: flex;
    flex-direction: row;
    border: 3px solid #919191;
}

.thumbnails {
    overflow-x: scroll;
    overflow-y: none;
}

.thumbnails img {
    max-height: 131px;
    margin: .2em;
}