anchor.diff:    margin: [0.75in, 1in, 0.75in, 1in]
   ----
   
  +The order of elements in a measurement array is the same as it is in CSS:
  +
  +. top
  +. right
  +. bottom
  +. left
  +
   === Colors
   
   The theme language supports color values in three formats:
  
positive.code: Even though the built-in fonts require the content to be encoded in WINANSI, _you still type your AsciiDoc document in UTF-8_.
  Asciidoctor PDF encodes the content into WINANSI when building the PDF.
  Any characters in your AsciiDoc document that cannot be encoded will be replaced with an underscore (`_`).
  
  === Custom fonts
  
  
negative.code: 
  ////
  Topics remaining to document:
  * line height and line height length (and what that all means)
  * title page layout / title page images (logo & background)
  * document that unicode escape sequences can be used inside double-quoted strings
  ////
  
  The theming system in Asciidoctor PDF is used to control the layout and styling of the PDF file that Asciidoctor PDF generates from AsciiDoc.
  