code: @Override
      public void appendTo( CssFormatter formatter ) {
          if( type == UNKNOWN ) {
              eval( formatter );
          }
          switch( type ) {
              case COLOR:
                  formatter.appendColor( value, toString() );
                  break;
              case STRING:
                  SelectorUtils.appendToWithPlaceHolder( formatter, toString(), 0, true, this );
                  break;
              case RULESET:
                  rule.appendPropertiesTo( formatter );
                  break;
              default:
                  super.appendTo( formatter );
          }
      }
docs: {@inheritDoc}