anchor.diff:  //          it belongs to the signified medium.
   //
   media
  -    : MEDIA_SYM medium (COMMA medium)*
  -        LBRACE
  -            ruleSet
  +    : MEDIA_SYM WS+ medium (WS* COMMA WS* medium)* WS*
  +        LBRACE WS*
  +            (ruleSet WS*)*
           RBRACE
  +    -> ^(MEDIA_SYM medium+ ruleSet*)
       ;
   
   // ---------    
  
positive.code: // Import.  Location of an external style sheet to include in the ruleset.
  //
  cssImport
      : IMPORT_SYM WS* cssImportLocation  (WS* medium (WS* COMMA WS* medium)*)? WS* SEMI
      -> ^(IMPORT cssImportLocation medium*)
      ;
      
  
negative.code: // Character set.   Picks up the user specified character set, should it be present.
  //
  charSet
      : CHARSET_SYM WS+ STRING WS* SEMI
      -> ^(CHARSET STRING)
      ;
  
  