<!doctype html> <meta charset="utf-8"> <link rel="help" href="https://html.spec.whatwg.org/#the-details-and-summary-elements"> <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1804925"> <link rel="match" href="details-revert-ref.html"> <style> summary { display: revert; counter-increment: revert; list-style: revert; } </style> <details> <summary>Example</summary> </details> <details open> <summary>Example</summary> </details>