anchor.diff:  
   === Custom Fonts
   
  -The limited character set of WINANSI, or the bland look of the built-in fonts, may motivate you to load your own font.
  +The limited character set of WINANSI, or the plain look of the built-in or bundled fonts, may motivate you to incorporate your own fonts.
   Custom fonts can enhance the look of your PDF theme substantially.
   
   IMPORTANT: In order for a third-party font to work properly with Prawn (and hence Asciidoctor PDF), several modifications are required.
  
positive.code: * bold
  * bold_italic
  
  You'll need all four variants to support AsciiDoc content properly.
  Otherwise, the converter will either crash or revert to the fallback font, depending on how your theme is configured.
  If one of the variants is missing from your collection, you can simply reuse the normal variant in its place.
  
  WARNING: Asciidoctor PDF cannot italicize a font dynamically like a browser can, so the italic styles are required.
  
  Once you've obtained the TTF files, put them in the directory inside 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: ----
  font:
    catalog:
      merge: false # set value to true to merge catalog with theme you're extending
      Roboto:
        normal: roboto-normal.ttf
        italic: roboto-italic.ttf
  