Outline from Requirements

Build the heading skeleton of a field-guide page — headings only, filler content allowed: exactly one <h1>; exactly three <h2> chapters; exactly two <h3> sections under each chapter (six total); at least one <h4> inside the third chapter; a <footer>; every heading has visible text; levels never skip. Include the full document skeleton (doctype, lang, charset, title).

Difficulty: advanced