This site <a href="https://en.wikipedia.org/wiki/Touhou_Project_fandom#Bad_Apple!!:~:text=demoscene">demos</a> <a href="https://www.youtube.com/watch?v=FtutLA63Cp8"><i>Bad Apple</i></a> with no JS, no CSS, and an impressively minimal subset of HTML. See:
<ul>
<li><a href=/dialog>No JS, no CSS, & no HTML tags except &lt;dialog open&gt; & &lt;br&gt;</a>. Even works over curl.
<li><a href=/zero>No JS, no CSS, & no HTML tags at all!</a>
<li><a href=/explainer>Explainer</a>