anchor.diff:        bold_italic: roboto-bold_italic.ttf
   ----
   
  -CAUTION: You must declare all four variants.
  +If you use this form, you must declare all four variants.
   If you're missing the font file for one of the variants, configure it to use the same font file as the normal variant.
  +
  +If your font only has a single variant, assign the font path to the font key directly.
  +
  +[source,yaml]
  +----
  +font:
  +  catalog:
  +    merge: false # set value to true to merge catalog with theme you're extending
  +    VLGothic: vlgothic.ttf
  +----
  +
  +Font paths can be absolute or relative.
  +Absolute paths are used as is.
  +Relative font paths are resolved from the <<Configuring the Font Search Path,font search path>>.
  +You can also use the `GEM_FONTS_DIR` keyword to refer to the location of the bundled fonts.
   
   You can add any number of fonts to the catalog.
   Each font must be assigned a unique key, as shown here:
  
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
  