anchor.diff:  
   This behavior differs from the default behavior in Prawn, which simply crashes.
   
  +To prevent this warning, you need to provide a TrueType font when using caracters outside the WINANSI set (callout numbers for example).
  +
   For more information about how Prawn handles character encodings for built-in fonts, see https://github.com/prawnpdf/prawn/blob/master/CHANGELOG.md#vastly-improved-handling-of-encodings-for-pdf-built-in-afm-fonts[this note in the Prawn CHANGELOG].
   ****
  +
   
   === Bundled Fonts
   
  
positive.code: IMPORTANT: The https://github.com/asciidoctor/asciidoctor-pdf/blob/master/data/themes/default-theme.yml[default theme] has a different set of values which are not shown in this guide.
  
  When creating a theme, all keys are optional.
  Required keys are provided by the base theme.
  Therefore, you only have to declare keys that you want to override.
  
  [#keys-page]
  
negative.code: All the available keys are documented in <<Keys>>.
  The converter uses the information from the theme map to help construct the PDF.
  
  
  [WARNING]
  ====
  If you start a new theme form scratch, be sure to provide a TrueType font familly for all base text sections (`base`, `literal`, `code`). Base theme only use built-in AFM fonts and some glyphs like callout numbers will be missing.
  ====
  
  [TIP]
  ====
  Instead of creating a theme from scratch, another option is to download the https://github.com/asciidoctor/asciidoctor-pdf/blob/master/data/themes/default-theme.yml[default-theme.yml] file from the source repository.
  