Child parent break propagation with break-before page
According to the specification:
3.1.1. Child→Parent Break Propagation Since breaks are only allowed between siblings, not between a box and its container (see Possible Break Points), break values applied to children at the start/end of a parent are propagated to the parent, where they can take effect.
https://drafts.csswg.org/css-break-3/#break-propagation
If I understand correctly it means that we should not add a blank page before the first section in this document: break-before-child-parent-propagation.html
<main>
<section>
<h2>Section 1</h2>
<p>This is a paragraph.</p>
</section>
</main>
The break-before is only allowed between siblings but <section>
has not sibling. So we should not break between <section>
and its container <main>
.