Main Page Title (Most Important)

Section 1: Introduction

Subsection 1.1: What is HTML?

Subsection 1.2: Why Use Headings?

Section 2: Using Headings

Subsection 2.1: Best Practices

Sub-subsection 2.1.1: SEO Tips

Sub-subsection 2.1.2: Accessibility

A Note on Importance

The Least Important Heading (Very Specific Detail)