On the demo page [1], the <main> element starts with an <hr>. That doesn’t seem right. The <hr> element is meant for section breaks (where there is content both before and after the <hr> element), not for decorative horizontal lines.
If we're really being pedantic, all uses of <hr> elements on that page are contrary to the spec's desires.
> The hr element represents a paragraph-level thematic break, e.g. a scene change in a story
> There is no need for an hr element between the sections themselves, since the `section` elements and the `h1` elements imply thematic changes themselves
https://html.spec.whatwg.org/multipage/grouping-content.html...
If it isn't clear, I find it a bit silly :)