title: how to change QAction background color using stylesheets (css)?
body: <p>I have some QActions in my QToolBar.
  QAction doesn't have any stylesheets, so I am trying to use QToolBar stylesheet to change QAction background color. It works for every QActions in QToolBar</p>
  
  <pre><code>QToolButton{ background: red; }
  </code></pre>
  
  <p>But I need to change some QAction background to red and some to green.</p>
  
  <p>I've tried this to change only one QAction</p>
  
  <pre><code>QToolButton:nth-of-type(3){ background: red; }
  </code></pre>
  
  <p>but it doesn't work.</p>
  
  <p>Any idea how to change backgroun only for some QActions?</p>