styles.css

body {
    margin: 0 auto;
    padding: 0;
    font-family: 'Roboto', serif;
    line-height: 1.7;
    font-size: 12px;
    max-width: 705px;
}

video {
    width: 100%;
}

.transcript-container {
    margin: 0 7%;
    padding-top: 10px;
}

.transcript-container span.highlighted {
    color: #ff9900;
}

.video .mejs__controls {
    background: #ff9900;
}

.video .mejs__volume-slider {
    background: #ff9900;
}

@media screen and (min-width: 768px) {
    body {
        font-size: 16px;
    }
    .transcript-container {
        margin: 0;
    }
    .container {
        margin-top: 30px;
    }
}