Proper heading hierarchy (H1-H6)What it checks and how to fix it

What it checks

Reads the visible headings (H1 to H6) in document order. Flags a missing H1, more than one H1, empty headings, skipped levels (an H2 followed by an H4) and a first heading that is not an H1. Warns when the only problem is several H1s, fails on any other problem and passes when there is none.

Why it matters

Screen reader users navigate a page by its headings, and skipped or empty levels leave them guessing where they are. Search engines and AI assistants use the same outline to work out the main topic and how sections relate. A page without an H1 does not state its subject anywhere.

How to fix it

Give the page one H1 that states its topic, and nest the rest without skipping levels. Choose heading levels for
structure and style them with CSS rather than picking a level for its size.

<h1>DMARC setup guide</h1>
  <h2>Before you start</h2>
  <h2>Step 1: publish a p=none record</h2>
    <h3>Reading the aggregate reports</h3>
  <h2>Step 2: move to quarantine</h2>

Things that look like headings but are not (card titles in a footer, a "Newsletter" label) can be a styled <p> or
<div>. Remove empty heading tags left behind by the CMS.