A CodePen by Jan Reimers. Overlay - an overlay in CSS, hiding and showing up again with a little jQuery

index.html

<h1>This is some Content</h1>
<p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
<p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
<a class="showoverlay">Show that Overlay again</a>
<div class="overlay">
  <div class="box">
    <span class="close fontawesome-remove-sign"></span>
    <h2>Overlay</h2>
    <p>This is some Content inside the Overlay</p>
    <p>Hide the Overlay by clickin' the button in the top-right corner</p>
  </div>
</div>

script.js

$('.close').click(function() {
 $('.overlay').hide();                 
});

$('.showoverlay').click(function() {
 $('.overlay').show();                 
});

style.css

@import url(http://weloveiconfonts.com/api/?family=fontawesome);

/* fontawesome */
[class*="fontawesome-"]:before {
  font-family: 'FontAwesome', sans-serif;
}
* { box-sizing: border-box }
.overlay {
  position: absolute;
  top: 0;
  left: 0;
  background: rgba(100, 100, 100, 0.8);
  width: 100%;
  height: 100%;
}
.box {
  background: #fff;
  width: 500px;
  height: 200px;
  margin: 50px auto;
  padding: 5px 15px;
  border-radius: 15px;
  box-shadow: 0 0 20px 0 #303030;
}
.close {
  float: right;
  font-size: 2em;
  cursor: pointer;
}
a.showoverlay {
  color: Blue;
  text-decoration: underline;
  cursor: pointer;
}