html, body {
    margin: 0;
    padding: 0;
    background: #eee;
    font: 16px Arial, sans-serif;
    color: #444;
}

.captions {
    margin: 2rem;
}
.captions output {
    display: block;
    background: #444;
    color: #fff;
    height: 100px;
    border: 1px solid #999;
    padding: 1rem;
    margin: 0;
    overflow-y: scroll;
    overflow-x: hidden;
}