anchor.diff:      font_size: $heading_h3_font_size
   
   |font_style
  -|<<font-styles,Font style>>
  +|<<font-styles,Font style>> +
  +(default: _inherit_)
   |title_page:
     subtitle:
       font_style: bold_italic
  
positive.code:     text_transform: uppercase
  
  |margin_top
  |<<measurement-units,Measurement>>
  |title_page:
    revision:
      margin_top: 13.125
  |===
  
  . Page backgrounds do not currently work when using AsciidoctorJ PDF.
  
negative.code:     text_transform: uppercase
  
  |line_height
  |<<values,Number>> +
  (default: $heading_line_height)
  |title_page:
    title:
      line_height: 0.9
  
  |top
  |Percentage^[3]^ +
  (default: 40%)
  |title_page:
    title:
      top: 55%
  
  |margin_top
  |<<measurement-units,Measurement>> +
  (default: 0)
  |title_page:
    title:
      margin_top: 13.125
  
  |margin_bottom
  |<<measurement-units,Measurement>> +
  (default: 0)
  |title_page:
    title:
      margin_bottom: 5
  
  3+|*Key Prefix:* title_page_subtitle
  
  |font_color
  |<<colors,Color>> +
  (default: _inherit_)
  |title_page:
    subtitle:
      font_color: #181818
  
  |font_family
  |<<fonts,Font family name>> +
  (default: _inherit_)
  |title_page:
    subtitle:
      font_family: Noto Serif
  