title: Vertical align middle button in div
body: <p>I am trying to vertically align this button in the center of the modal-footer <code>div</code>.  Here is a link to my JSFiddle: <a href="https://jsfiddle.net/kris_redden/34jyLpok/" rel="noreferrer">https://jsfiddle.net/kris_redden/34jyLpok/</a></p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.modal-footer {
    background-color: #2A3E5D;
    color: white;
    height: 100px;
    padding: 2px 16px;
  }
  
  .wrapper-div {
    vertical-align: middle
  }
  
  .button {
    background: #e8e8e8;
    display: inline-block;
    font-size: 12px position: relative;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="modal-footer"&gt;
    &lt;div class="wrapper-div"&gt;
      &lt;button type="button" class="button"&gt; Submit Filters &lt;/button&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I'm not sure what needs to change in order for this to be vertically aligned in the center of the blue modal-footer div.  I know can accomplish this in a hacky way by putting margins on the button but that isn't what I want to do. </p>