i should i do if i want to use css?

var styles = new iTextSharp.text.html.simpleparser.StyleSheet();
                     styles.LoadStyle("Lastname", "size", "50pt");
                     hTextWriter.Write("<div class=\"Lastname\">");


                     hTextWriter.Write("<p>Kurac</p>");
                     hTextWriter.Write("</div>");




                     String strHtml1 = sw.ToString();

                     var hw = new iTextSharp.text.html.simpleparser.HTMLWorker(document);
                     hw.SetStyleSheet(styles);
                     hw.Parse(new StringReader(strHtml1));
                     document.Close();