title: Height of parent div is zero with finite height child divs in safari
body: <p>Though I have tried using clear fix but that didn't solved the purpose</p>
  
  <p>code looks like</p>
  
  <pre><code>&lt;div&gt;
  &lt;div flex="25"&gt;
      &lt;md-card&gt;
      &lt;/md-card&gt;
  &lt;/div&gt;
  &lt;div flex="25"&gt;
      &lt;md-card&gt;
      &lt;/md-card&gt;
  &lt;/div&gt;
  &lt;div flex="50"&gt;
      &lt;md-card&gt;
      &lt;/md-card&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Now all the three internal divs are taking height 0 px in safari but working fine according to the angular material flex technique in chrome and safari.</p>