title: CSS counter on hidden submenu
body: <p>I'm trying to make a dropdown menu using nested <code>&lt;ul&gt;</code>,  every <code>&lt;li&gt;</code> displaying a number generated with CSS Counters.</p>
  
  <p>Sub-menus are hidden with <code>display:none</code> when not hovered.</p>
  
  <p>My problem is that counters are not incremented when an element has <code>display</code> set to <code>none</code>.</p>
  
  <p>Do you know a CSS property to prevent this?</p>
  
  <p>If I replace <code>display: none</code> by <code>visibility: hidden</code>, it's working but I'm not sure if it's nice to use this for my menu, are there any traps?</p>