css/css-display/display-contents-details.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Display: display:contents and HTML details and summary elements</title>
<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-html">
<link rel="match" href="display-contents-pass-ref.html">
<style>
  html { font-kerning: none; font-feature-settings: "kern" off; }
  details, summary {
    all: initial;
    border: 10px solid red;
    display: contents;
  }
  details::details-content {
    display: contents;
  }
</style>
<p>You should see the word PASS below.</p>
P<details open><summary>A</summary><span>S</span></details>S