<!DOCTYPE HTML> <title>Fonts and margins of HTML headers</title> <style type="text/css"> div { border: medium solid blue } </style> <div><h1>Level 1</h1></div> <article> <div><h1>Level 2</h1></div> <nav> <div><h1>Level 3</h1></div> </nav> <section> <aside> <div><h1>Level 4</h1></div> </aside> </section> <section> <nav> <nav> <div><h1>Level 5</h1></div> <aside> <div><h1>Level 6</h1></div> </aside> </nav> </nav> </section> </article>