PURE CSS POPUP

This is pure css popup. no jquery or javascript needed to implement this popup.

HTML

<!-- thumbnail image wrapped in a link -->
<a href="#img1">
  <img src="http://insomnia.rest/images/screens/main.png" class="video_thumbnail">
</a>

<!-- lightbox container hidden with CSS -->
<a href="#_" class="lightbox_video_thumbnail" id="img1">
 
  <iframe width="560" height="315" src="https://www.youtube.com/embed/bPAOKt1gtnM" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
</a>

CSS

/** LIGHTBOX MARKUP **/
.video_thumbnail {
  max-width: 40%;
}

.lightbox_video_thumbnail {
	/** Default lightbox to hidden */
	display: none;

	/** Position and style */
	position: fixed;
	z-index: 999;
	width: 100%;
	height: 100%;
	text-align: center;
	top: 0;
	left: 0;
	background: rgba(0,0,0,0.8);
}

.lightbox_video_thumbnail img {
	/** Pad the lightbox image */
	max-width: 90%;
	max-height: 80%;
	margin-top: 2%;
}

.lightbox_video_thumbnail:target {
	/** Remove default browser outline */
	outline: none;
  padding-top: 150px;

	/** Unhide lightbox **/
	display: block;
}