title: MaterializeCSS valing-wrapper responsiveness not working
body: <p>I am trying to align content in vertical and horizontal middle and also use <a href="http://materializecss.com/" rel="nofollow noreferrer">materializecss</a> columns to have 100% width when the window is on a smaller device and split equally across the window on larger devices:</p>
  
  <pre><code>&lt;div class="row valign-wrapper"&gt;
      &lt;div class="col s12 l6"&gt;
          A
      &lt;/div&gt;
      &lt;div class="col s12 l6 valign"&gt;
          B
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>See <a href="https://jsfiddle.net/h3e44zdq/" rel="nofollow noreferrer">JSFiddle</a></p>
  
  <p>Unfortunately on smaller devices it just stays split inline. Rather than dropping to a new line.</p>