Problems With Headers

If you use section titles (headers), the underline must be at least as long as the text.

Though you can make the underlines longer than the text, common practice throughout the docs is to to keep it the same length.

ちなみに

If you use an IDE with good reStructuredText support, it should point out this error correctly, for example if you use PhpStorm, enable the reStructuredText plugin.

Correct Syntax

================
This Is a Header
================

Another Header
==============


This Is Also Correct but Not Recommended
======================================================

Wrong Syntax

Another Header
------------