Numbered headings for GitBook PDFs

For example:

1 Main heading

Some text.

1.1 First subheading

More text.

1.2 Another subheading

Even more text.

1.2.1 A sub-sub heading

Running out of things to say.

Usage

{
  "plugins": ["chapter-headings"]
}

To adjust the style of the numbers, use:

h1:before, h2:before, h3:before, h4:before, h5:before {
  color: #aaa;
  width: 40px;
}