anchor.diff:    size: Letter
   |===
   
  -^[1]^ Page backgrounds do not currently work when using AsciidoctorJ PDF.
  +. Page backgrounds do not currently work when using AsciidoctorJ PDF.
   This limitation is due to a bug in Prawn 1.3.1.
   The limitation will remain until AsciidoctorJ PDF upgrades to Prawn 2.x (an upgrade that is waiting on AsciidoctorJ to migrate to JRuby 9000).
   For more details, see http://discuss.asciidoctor.org/Asciidoctor-YAML-style-file-for-PDF-and-maven-td3849.html[this thread].
  
positive.code: |margin_bottom: 9.600
  |===
  
  ^[1]^ `<n>` may be a number ranging from 1 to 6, representing each of the six heading levels.
  
  === Title page
  
  
negative.code: |center: '\{page-number}'
  |===
  
  . `<side>` can be `recto` (odd pages) or `verso` (even pages).
  `<align>` can be `left`, `center` or `right`.
  
  IMPORTANT: You must define a height for the running header or footer, respectively, or it will not be shown.
  