title: How do I give a CSS class priority over an id?
body: <p>I have a element like this:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>#idname{
    border: 2px solid black;
  }
  
  .classname{
    border: 2px solid gray;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id = "idname" class="classname"&gt;it is a test&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I want to give a bigger priority to its CSS class instead of its CSS id. Is it possible? <em>(In other word I want to set <code>gray</code>-color as its <code>border</code>)</em></p>