Credibility · 22 points
Heading structure
One check, stated three ways: what we measure, what would make it wrong, and how to confirm it yourself.
What this measures
The sequence of heading levels in document order and whether any level is skipped.
Where this check can be wrong
Skipped levels are a real accessibility problem but not a rendering one, and component libraries produce them by accident far more often than designers intend.
Verify it without taking our word for it
In your browser console: [...document.querySelectorAll('h1,h2,h3,h4,h5,h6')].map(h => h.tagName).join(' ').