/* Embedded YouTube players (docs/_ext/youtube.py): 16:9, full width up to 720 px. */
.youtube-embed {
    position: relative;
    width: 100%;
    max-width: 720px;
    aspect-ratio: 16 / 9;
    margin: 0 0 1.5em;
}
.youtube-embed iframe {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: 0;
}