title: Textarea to expand similar to Medium Editor?
body: <p>I noticed that the Textarea of the <a href="https://medium.com/new-story" rel="nofollow noreferrer">Medium</a> editor does not have a scroll bar that expands as text is typed and also expands the entire webpage instead of having a fixed height.</p>
  
  <p><strong>Demo:</strong></p>
  
  <p><strong>Before typing:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/6WwBd.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6WwBd.jpg" alt="The Textarea does not have a scroll bar"></a></p>
  
  <p><strong>After typing:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/vdjzu.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vdjzu.jpg" alt="enter image description here"></a></p>
  
  <p>Notice that the text area expanded the entire browser webpage instead of expanding the textarea only. </p>
  
  <p><strong>How do I get this done in CSS?</strong></p>
  
  <p>This is what I have right now:</p>
  
  <pre><code>.postbox-desc-input{
      border:none;
      outline: none;
      font-size: 18px;
      font-weight: 600px;
      width: 100%;
      height: 100%;
  }
  </code></pre>
  
  <p><strong>EDIT: HTML Code</strong></p>
  
  <pre><code>&lt;div id="pb-expan-postbox"&gt;
        &lt;textarea id="pb-descbox" placeholder="Type your Text here" class="postbox-desc-input"&gt;&lt;/textarea&gt;
  &lt;/div&gt;
  </code></pre>