anchor.diff:    title:
       top: 55%
   |===
  +
  +[#title-top]
  +=== top
  +
  +The absolute top position of the logo.
  +The `%` unit is a percentage of the content height, starting from the top of the content area.
  +The `vh` unit is a percentage of the page height, starting from the top of the page.
   
   [#subtitle]
   == title-page-subtitle
  
positive.code:     top: 25%
  |===
  
  [#top]
  === top
  
  The `%` unit is relative to content height; `vh` unit is relative to page height.
  
  [#title]
  == title-page-title
  
negative.code:   title:
      text-transform: smallcaps
  
  |<<title-top,top>>
  |xref:measurement-units.adoc[Measurement] +
  (default: `40%`)
  |[source]
  