/*
echo sha256-$(cat style.css|openssl dgst -sha256 -binary|openssl base64 -A)
*/
html, body {
    font-family: sans-serif;
    text-align: center;
    background-color: #181a1b;
    border-color: #575757;
    color: #e8e6e3;
}
a {
    display: block;
    font-size: 2em;
    margin: 0.5em;
    font-weight: bold;
    color: #e8e6e3;
}
div {
    width: 75vw;
    display: block;
    margin: 0 auto;
}
div > div {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    padding-top: 25px;
    height: 0;
}
div > div > iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}