title: How to make scrollable pop up box?
body: <p><a href="https://codepen.io/anon/pen/dWaWor" rel="nofollow noreferrer">https://codepen.io/anon/pen/dWaWor</a></p>
  
  <p>When I click on the button "Creation Process" I cannot scroll in the lightbox.</p>
  
  <p>The lightbox has a fixed position because when I used absolute the background messes up. The lightbox is a white background.</p>
  
  <pre><code>&lt;section id="lightbox"&gt;
     &lt;i id="x" class="fa fa-times-circle"aria-hidden="true"&gt;&lt;/i&gt;
     &lt;p class="large"&gt;hi&lt;/p&gt;
  &lt;/section&gt;
  </code></pre>
  
  <p>></p>
  
  <pre><code>#lightbox {
    height:100%;
    width:100%;
    display: none;
    position: fixed;
    top:0;
    left:0;
    background: #fff;
    z-index:1;
  }
  </code></pre>
  
  <p>></p>
  
  <pre><code> var btn_process = document.getElementById('creation-process');
   var lightbox = document.getElementById('lightbox');
   var x = document.getElementById('x');
  
   btn_process.onclick = function () {
      lightbox.style.display = 'block';
  };
  
  x.onclick = function () {
      lightbox.style.display = 'none';
  }
  </code></pre>