title: how could change element class in media query
body: <pre><code>&lt;button id='123'  type="button" class="btn btn-xs btn-danger"&gt;
  &lt;i class="fa fa-trash"&gt;&lt;/i&gt;
  &lt;/button&gt;
  
  
  @media only screen and (min-width: 600px) { .... }
  </code></pre>
  
  <p>I hope in min-width:600px , 
  change the Button id='123' class="btn btn-lg btn-danger"</p>
  
  <p>Please Help me !</p>