JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Diskussion aus: <a href="https://www.html.de">html.de</a></h1>
<a href="#bild_popup">
   <img class="beispielbild" src="http://www.chroface.com/user-content/templates/base/downloads/hintergrundbilder/sonnenuntergang-winter-landschaft-natur-hintergrundbild.jpg">
</a>
<p>
   Klick das Bild
</p>

<div id="bild_popup" class="popup_container">
	<div class="popup">
		<h2>Titel deines Bildes</h2>
		<a class="close" href="#">&times;</a>
		<div class="content">
			<img class="popupbild" src="http://www.chroface.com/user-content/templates/base/downloads/hintergrundbilder/sonnenuntergang-winter-landschaft-natur-hintergrundbild.jpg">
      Vielleicht noch eine Bildunterschrift
		</div>
	</div>
</div>
<p style="position: absolute; bottom: 0; left: 0;">
angelehnt und angepasst von: <br><a href="https://codepen.io/imprakash/pen/GgNMXO">https://codepen.io/imprakash/pen/GgNMXO</a>
</p>

CSS

.popup_container {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(0, 0, 0, 0.7);
  transition: opacity 500ms;
  visibility: hidden;
  opacity: 0;
}
.popup_container:target {
  visibility: visible;
  opacity: 1;
}

.popup {
  margin: 70px auto;
  padding: 20px;
  background: #fff;
  border-radius: 5px;
  width: 30%;
  position: relative;
  transition: all 5s ease-in-out;
}

.popup h2 {
  margin-top: 0;
  color: #333;
  font-family: Tahoma, Arial, sans-serif;
}
.popup .close {
  position: absolute;
  top: 20px;
  right: 30px;
  transition: all 200ms;
  font-size: 30px;
  font-weight: bold;
  text-decoration: none;
  color: #333;
}



@media screen and (max-width: 700px){
  .box{
    width: 70%;
  }
  .popup{
    width: 70%;
  }
}

.beispielbild {
  width: 20%;
}

.popupbild {
  max-width: 100%;
}