title: Custom class to fieldset in Joomla module
body: <p>I am creating a new module and I need/want to add a custom CSS or ID to the entire fieldset, is it possible? How?</p>
  
  <p>My code is:</p>
  
  <pre><code>&lt;config&gt;
      &lt;fields name="params"&gt;
          &lt;fieldset  name="mymodule" &gt;
  </code></pre>
  
  <p>What do I have to do to have a custom CSS?</p>