div#course {
    max-width: 90ch;
    background-color: #99BBEE;
    color: black;
    margin: 2em auto 2em auto;
    padding: 1em;
    border: 4px solid black;
    text-align: left;
    opacity: 0.8;
}

div#course h1,
div#course h2,
div#course h3 {
    color: black;
}

div#course h2 {
    margin-top: 1.25em;
}

.center {
    text-align: center;
}

div#course ul {
    padding-left: 1em;
}

div#course ul.org-ul {
    padding: 0;
    margin: 0.25em 0;
}

div#course ul.org-ul li {
    padding: 0;
    margin: 0 0 0 2.5ch;
}

div#course p {
    margin: 0.25em 0;
}

div#video {
    max-width=100%;
    width=100%;
    background-color: #99BBEE;
    color: black;
    margin: 1em auto;
    padding: 1em;
    border: 4px solid black;
    text-align: left;
    opacity: 0.8;
}

div#video h1 {
    text-align: center;
}

div#video video {
    display: block;
    margin: 0 auto;
}