anchor.diff:  The theming system in Asciidoctor PDF is used to control the layout and styling of the PDF file Asciidoctor PDF generates from AsciiDoc.
   This document describes how the theming system works, how to define a custom theme in YAML and how to activate the theme when running Asciidoctor PDF.
   
  -IMPORTANT: If you're using a custom theme, you're expected to override some of keys described in the sections below, in particular fonts.
  -If you don't define your own fonts, the built-in PDF fonts will be used.
  +IMPORTANT: If you're using a custom theme, you're expected to bring your own fonts or declare the fonts from the default theme.
  +If you don't declare your own fonts, the built-in PDF (afm) fonts will be used, which only support WINANSI characters (similar to Basic Latin).
   
   toc::[]
   
  
positive.code: * bold_italic
  
  You'll need all four styles to support AsciiDoc content properly.
  _Asciidoctor PDF cannot italicize a font that is not italic like a browser can._
  
  Once you've obtained the TTF files, put them into a directory in your project where you want to store the fonts.
  It's recommended that you name them consistently so it's easier to type the names in the theme file.
  
negative.code: 
  === Bundled Fonts
  
  Asciidoctor PDF bundles several fonts that are used by the default theme.
  You can also use these fonts in your custom theme by simply declaring them.
  These fonts provide more characters than the built-in PDF fonts, but still only a subset of UTF-8 (to reduce the size of the gem).
  
  The family name of the fonts bundled with Asciidoctor PDF are as follows:
  
  