code: @Override
      public void appendTo( CssFormatter formatter ) {
          if( css.startsWith( "@charset" ) ) {
              if( formatter.isCharsetDirective() ) {
                  return; // write charset only once
              }
              formatter.setCharsetDirective();
              formatter = formatter.getHeader(); 
          } else if( css.startsWith( "@import" ) ) {
              formatter = formatter.getHeader();
          }
          formatter.getOutput();
          SelectorUtils.appendToWithPlaceHolder( formatter, css, 1, false, this );
          formatter.newline();
      }
docs: {@inheritDoc}