anchor.diff:  
   [source,yaml]
   ----
  -base:
  +table:
     background-color: transparent
   ----
   
  
positive.code: . The path is resolved relative to base_dir.
  . The target of the image macro is resolved relative to `imagesdir`.
  If the image macro syntax is not used, the value is resolved relative to the base directory, which defaults to the document directory.
  . By default, page background images are automatically scaled to fit the bounds of the page (i.e., `fit=contain`).
  The size of the background can be controlled using any of the sizing attributes on the image macro (i.e., fit, pdfwidth, scaledwidth, or width).
  If the recto (right-hand, odd-numbered pages) or verso (left-hand, even-numbered pages) background is specified, it will be used only for that side.
  If a background image isn't specified for a side, the converter will use the default page background image (`page-background-image`), if specified.
  To disable the background for a side, use the value `none`.
  . Controls whether the `page-number` attribute is accessible to the running header and footer content specified in the theme file.
  Use the `noheader` and `nofooter` attributes to disable the running header and footer, respectively, from the document.
  . Enables generation of the http://milan.kupcevic.net/ghostscript-ps-pdf/#marks[pdfmark] file, which contains metadata that is fed to Ghostscript when optimizing the PDF file.
  
negative.code: The keys in this category control the size, margins and background of each page (i.e., canvas).
  We recommended that you define this category before all other categories.
  
  NOTE: The background of the title page can be styled independently of other pages.
  See <<Title Page>> for details.
  
  [cols="3,4,5l"]
  