Minimal Responsive Gallery Lightbox with Pure HTML / CSS

A simple, responsive galley lightbox for showcasing your favorite images, built using pure HTML and CSS. Clicking on the thumb will display all your images in a responsive, navigatable and closeable lightbox popup.

How to use it:

Add thumbnails and lightbox containers to your webpage.

<a href="#img1">
  <img class="thumb" src="thumb-1.jpg">
</a>
<!-- lightbox container hidden with CSS -->
<div class="lightbox" id="img1">
  <a href="#img3" class="light-btn btn-prev">prev</a>
    <a href="#_" class="btn-close">X</a>
    <img src="images/1.jpg">
  <a href="#img2" class="light-btn btn-next">next</a>
</div>
<a href="#img2">
<img class="thumb" src="thumb-2.jpg">
</a>
<!-- lightbox container hidden with CSS -->
<div class="lightbox" id="img2">
  <a href="#img1" class="light-btn btn-prev">prev</a>
    <a href="#_" class="btn-close">X</a>
    <img src="2.jpg">
  <a href="#img3" class="light-btn btn-next">next</a>
</div>
<a href="#img3">
<img class="thumb" src="thumb-3.jpg">
</a>
<!-- lightbox container hidden with CSS -->
<div class="lightbox" id="img3">
  <a href="#img2" class="light-btn btn-prev">prev</a>
    <a href="#_" class="btn-close">X</a>
    <img src="3.jpg">
  <a href="#img1" class="light-btn btn-next">next</a>
</div>

The core CSS styles.

.thumb {
  max-height: 171px;
  border: solid 6px rgba(5, 5, 5, 0.8);
}
.lightbox {
  position: fixed;
  z-index: 999;
  height: 0;
  width: 0;
  text-align: center;
  top: 0;
  left: 0;
  background: rgba(0, 0, 0, 0.8);
  opacity: 0;
}
.lightbox img {
  max-width: 90%;
  max-height: 80%;
  margin-top: 2%;
  opacity: 0;
}
.lightbox:target {
  /** Remove default browser outline */
  outline: none;
  width: 100%;
  height: 100%;
  opacity: 1 !important;
}
.lightbox:target img {
  border: solid 17px rgba(77, 77, 77, 0.8);
  opacity: 1;
  webkit-transition: opacity 0.6s;
  transition: opacity 0.6s;
}
.light-btn {
  color: #fafafa;
  background-color: #333;
  border: solid 3px #777;
  padding: 5px 15px;
  border-radius: 1px;
  text-decoration: none;
  cursor: pointer;
  vertical-align: middle;
  position: absolute;
  top: 45%;
  z-index: 99;
}
.light-btn:hover { background-color: #111; }
.btn-prev { left: 7%; }
.btn-next { right: 7%; }
.btn-close {
  position: absolute;
  right: 2%;
  top: 2%;
  color: #fafafa;
  background-color: #92001d;
  border: solid 5px #ef4036;
  padding: 10px 15px;
  border-radius: 1px;
  text-decoration: none;
}
.btn-close:hover { background-color: #740404; }