/**
  * Returns a link to the stylesheet file.
  *
  * @return an HtmlTree for the lINK tag which provides the stylesheet location
  */
 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;
 }