title: Unable to set height of a div inside ion-content in ionic based application
body: <p>I am a newbie to ionic. I am trying to centre 2 divs regardless of the amount of content, inside an <code>ion-content</code> tag on a page. Setting height to some percentage value is not working. Attaching a custom <code>centre</code> class is also not affecting the position of the divs. They are still stacked on top of each other taking only the space required. </p>
  
  <p>Below is HTML:</p>
  
  <pre><code>&lt;ion-content class="padding tab-dash-content centre"&gt;
    &lt;div class="section1 padding centre"&gt;
      &lt;h3&gt;Section 1&lt;/h2&gt;
      &lt;h5&gt;
        Sub Heading
      &lt;/h5&gt;
      &lt;p&gt;
        Some multi Line text
      &lt;/p&gt;
    &lt;/div&gt;      
    &lt;div class="section2 padding centre"&gt;
      &lt;h3&gt;Section 2&lt;/h3&gt;        
      &lt;h5&gt;
        Sub Heading
      &lt;/h5&gt;
      &lt;p&gt;
        Some multi line text
      &lt;/p&gt;
    &lt;/div&gt;
  &lt;/ion-content&gt;
  </code></pre>
  
  <p>The CSS:</p>
  
  <pre><code>.centre { 
      float: none;
      margin-left: auto; 
      margin-right: auto; 
  }
  
  .section1,
  .section2 {
      border: 2px solid #ffa733;
      height: 50%;
      width: 100%;
  }
  </code></pre>