title: Load custom css depending on url query string and maintain user on that query string
body: <p>Is it possible to have a custom css class for a page accessed by a custom query string? And to maintain that query string while the user is navigating inside the website?</p>
  
  <p>For example, users from <code>example.com/page123?&amp;example1</code> will have a custom css like</p>
  
  <pre><code>.example1 {
  display: block
  }
  </code></pre>
  
  <p>and users accessing <code>example.com/page123</code> will see</p>
  
  <pre><code>.example1 {
  display: none
  }
  </code></pre>
  
  <p>But if the user is already in page123, and it goes to page1234, the query string will persist and the class example1 with display: block will also be applied. Just to mention, I'm using Wordpress, and PHP, jQuery or Plugins are allowed.</p>