title: Override global css with pure javascript
body: <p>I have the following situation:</p>
  
  <pre><code>.my-nice-class {
    max-width: 90%;
    max-height: 90%;
  }
  </code></pre>
  
  <p>This code lies in the first <code>&lt;style&gt;...&lt;/style&gt;</code> in the html page.
  I would like to override this global css, by setting for instance new properties values like in the example below:</p>
  
  <pre><code>.my-nice-class {
    max-width: 40%;
    max-height: 40%;
  }
  </code></pre>
  
  <p>How can I accomplish this with pure Javascript?</p>
  
  <p>Thank you all,</p>
  
  <p>Nano</p>