anchor.diff:  
   [source,yaml]
   ----
  +extends: default
   footer:
     recto:
       right:
  
positive.code: 
  IMPORTANT: If you don't specify a height for either the header or footer key, it effectively disables the content at that periphery.
  
  If you define running header and footer content in your theme (including the height), you can still disable this content per document by setting the `noheader` and `nofooter` attributes in the AsciiDoc document header, respectively.
  
  If you extend either the base or default theme, and don't specify content for the footer, the current page number will be added to the right side on recto pages and the left side on verso pages.
  
negative.code: 
  [source,yaml]
  ----
  extends: default
  footer:
    columns: =100%
    recto:
  