See the suggestion by @muan at #3499 (comment):

<h1>GitHub</h1>
<h2>jsdom/jsdom</h2>
<div>
<article headinglevelstart="3">
   <h1>jsdom</h1>
   <h2>Basic usage</h2>
   <h2>Customizing jsdom</h2>
   <h3>Simple options</h3>
   ...
 </article>
</div>

cc @whatwg/a11y