Responsive YouTube Video Embeds

How to embed a YouTube video in your site and have it responsive, so it scales down on a mobile device

To have a YouTube video be displayed responsive in your page, first wrap it into a container div:

<div class="video-container">
  <iframe src="https://www.youtube.com/embed/...." frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</div>

Then add this CSS to your site:

.video-container {
    overflow: hidden;
    position: relative;
    width:100%;
}

.video-container::after {
    padding-top: 56.25%;
    display: block;
    content: '';
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}