css/css-lists/counter-increment-inside-display-contents.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Lists: counter-increment on child of display:contents</title>
<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-lists/#counters-without-boxes">
<link rel="match" href="counter-7-ref.html">
<style>
  .inc { counter-increment: x }
  .reset-6 { counter-reset: x 6 }
  .contents { display: contents }
  .result::before { content: counter(x) }
</style>
<p>You should see the number 7 below.</p>
<div>
  <span class="reset-6"></span>
  <span class="contents">
    <span class="inc"></span>
  </span>
  <span class="result"></span>
</div>