anchor.diff:  
   * If you want to use icons font, don't change anything.
   
  -* If you want to use only PNG image files ( with AsciiDoc `icons` attribute ), 
  -just remove or comment 20. 
  +* If you want to use only PNG image files ( with AsciiDoc `icons` attribute ),
  +just remove or comment 20.
   +
   [source,css]
   ----
  
positive.code: endif::basebackend-docbook[]
  
  [role="lead"]
  Release v4.0.0 included the default Bootstrap theme and four more free themes  
  from http://bootswatch.com/[Bootswatch] template provider.
  
  If all those skins does not match your needs, you can either :
  
negative.code: [source,css]
  ----
  //@import "ionicons/ionicons.less";
  ----
  
  == Icons font support by Octicons
  
  If you don't want to use https://octicons.github.com/[Octicons],
  just remove or comment line 16.
  
  [source,css]
  ----
  //@import "octicons/octicons.less";
  ----
  
  == Admonition Blocks
  