heading-order
Heading levels should only increase by one
Why it matters
Screen reader users often navigate a page by jumping between headings. Skipped levels (e.g. an <h2> followed directly by an <h4>) make the page's structure confusing to scan this way.
How to fix it
Restructure headings so each level increases by exactly one at a time — an <h2> can be followed by another <h2> or an <h3>, never an <h4> or beyond.