anchor.diff:      start-at: toc
   |===
   
  -. To disable the background color for the page, set the value to white (i.e., FFFFFF).
  +1. To disable the background color for the page, set the value to white (i.e., FFFFFF).
   The color keyword `transparent` is not recognized in this context.
  -. By default, page background and foreground images are automatically scaled to fit the bounds of the page (i.e., `fit=contain`) and centered (i.e., `position=center`).
  +2. By default, page background and foreground images are automatically scaled to fit the bounds of the page (i.e., `fit=contain`) and centered (i.e., `position=center`).
   The size of the image can be controlled using any of the sizing attributes on the image macro (i.e., fit, pdfwidth, scaledwidth, or width) when `fit=none`.
   The position of the image can be controlled using the `position` attribute.
   If the recto (right-hand, odd-numbered pages) or verso (left-hand, even-numbered pages) background image is specified, it will be used only for that side (not available for the foreground image).
   If you define the keys using the flatten structure (e.g., `page-background-image-recto`), you can also set the default page background image (`page-background-image`), which will then be used as a fallback if a background image isn't specified for a given side.
   To disable the image, use the value `none`.
  -. Target may be an absolute path or a path relative to the value of the `pdf-themesdir` attribute.
  -. The margins for `recto` (right-hand, odd-numbered) and `verso` (left-hand, even-numbered) pages are calculated automatically from the margin-inner and margin-outer values.
  +3. Target may be an absolute path or a path relative to the value of the `pdf-themesdir` attribute.
  +4. The margins for `recto` (right-hand, odd-numbered) and `verso` (left-hand, even-numbered) pages are calculated automatically from the margin-inner and margin-outer values.
   These margins and used when the value `prepress` is assigned to the `media` document attribute.
   If no cover is specified, the recto margin is not applied to the title page.
   To apply the recto margin to the title page, but not include a cover, assign the value `~` to the `front-cover-image` attribute.
  -. The `cover` value is only recognized if the documet has a front cover page (i.e., `front-cover-image`).
  +5. The `cover` value is only recognized if the documet has a front cover page (i.e., `front-cover-image`).
   The `title`, `toc`, and `after-toc` values are only recognized if the title page is enabled (i.e., doctype is book or `title-page` attribute is set)
   The `toc` value only applies if the toc is in the default location (before the first page of the body).
   If value is `toc`, and the toc macro is used to position the toc, the start-at behavior is the same as if the toc is not enabled.
  
positive.code:   text-align: left
  |===
  
  . Controls the color of the bullet glyph that marks items in unordered lists and the number for items in ordered lists.
  . Controls the alignment of the list text only, not nested content (blocks or lists).
  
  [#keys-ulist]
  === Unordered List
  
negative.code:   font-style: bold
  |===
  
  1. The border is only used if a border color is specified and the border width is not explicitly set to 0.
  The border only works properly if the literal phrase does not have nested formatting.
  Otherwise, the border will be inherited, producing a less than desirable result.
  2. The border offset is the amount that the background and border swells around the text.
  It does not affect the distance between the formatted phrase and the phrases that surround it.
  
  [#keys-heading]
  