gecko/layout/reftests/counter-style/disclosure-styles.html

<style type="text/css">
  @counter-style disclosure-closed2 {
    system: extends disclosure-closed;
  }
  @counter-style disclosure-open2 {
    system: extends disclosure-open;
  }
  ul {
    padding: 0;
    list-style-position: inside;
  }
  .closed { list-style-type: disclosure-closed2; }
  .open { list-style-type: disclosure-open2; }
  p::before {
    content: counter(a, disclosure-closed) " ";
  }
</style>
<ul dir="ltr">
  <li class="closed">closed ltr
  <li class="open">open ltr
</ul>
<ul dir="rtl">
  <li class="closed">closed rtl
  <li class="open">open rtl
</ul>
<p dir="ltr">closed ltr
<p dir="rtl">closed rtl