Semantic HTML

You might say

The SEO check says my page is missing an H1. What does that mean?

HTML tags that mark each section's role in the document, such as headings, lists, and navigationWhen structuring a web page, semantic HTML tags mark content roles, such as headings for sections, nav for navigation, and ul for lists. Screen readers can navigate by headings; font size is visual styling, not structure. HTML allows multiple H1 elements on a page. Heading levels should reflect the content hierarchy so the outline is easy to follow.

Know first

HTML

Semantic HTML

A page's heading levels: click a section to see its tag

example.com

H1Lily's photography page

A main content heading

The outline is read by tags, not by font size
Heading levels show nesting; unnecessary skips can make the outline harder to follow

Biggest font size does not mean highest level: heading tags express structure, visual size is only styling.

Why heading levels have an order

Use H1 according to the content: HTML allows multiple H1s; check whether each marks a distinct main section instead of deleting one just because of the count.

Levels descend in order: H1→H2→H3 can express nested sections; skipping a level unnecessarily can make the outline harder to follow, but is not an HTML syntax error by itself.

Machines and people read it: Screen readers can navigate by headings; font size only affects appearance and cannot replace heading structure.

Quick checkChoose the best answer

A page has two H1s. Should one be removed right away?

Do not judge by the count alone; check that the headings and their levels express a clear outlineAs long as font sizes look right, any tag worksUse H1 on whatever text has the largest font size

You can say this to an AI Agent

Review this page's heading structure against its content. Do not treat multiple H1s as an error by themselves; make sure each heading level shows a clear parent-child relationship. Then use an outline view to confirm the structure and tell me which sections each heading introduces.

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