code: public HtmlTree getStyleSheetProperties() {
          String filename = configuration.stylesheetfile;
          DocPath stylesheet;
          if (filename.length() > 0) {
              DocFile file = DocFile.createFileForInput(configuration, filename);
              stylesheet = DocPath.create(file.getName());
          } else {
              stylesheet = DocPaths.STYLESHEET;
          }
          DocPath p = relativePath.resolve(stylesheet);
          HtmlTree link = HtmlTree.LINK("stylesheet", "text/css", p.getPath(), "Style");
          return link;
      }
docs: Returns a link to the stylesheet file.
  
  @return an HtmlTree for the lINK tag which provides the stylesheet location