ref: 6a7f989d7ba9c5e821fcacfa86a7dba566b3a38f
dir: /docs/layouts/shortcodes/youtube.html/
<div class="video-container"> <iframe class="youtube-player" type="text/html" width="100%" height="auto" src="https://www.youtube.com/embed/{{ index .Params 0 }}" allowfullscreen frameborder="0"> </iframe> </div>