从html字符串转换后，样式将不适用于pdf

Document document = new Document(PageSize.A4, 0, 0, 30, 65);
                PdfWriter.GetInstance(document, new FileStream(Server.MapPath(\"/\") + \"Temp/\" + \"parsetest11.pdf\", FileMode.Create));
                document.Open();
                string htmlTabel = \"<table width=\'660\' border=\'0\' cellspacing=\'0\' cellpadding=\'05\' class=\'myclass\'><tr><td>Welcome</td></tr></table>\";
                StringReader abc = new StringReader(htmlTabel);
                iTextSharp.text.html.simpleparser.StyleSheet styles = new iTextSharp.text.html.simpleparser.StyleSheet();
                styles.LoadStyle(\"myclass\", \"clspdf\", \"color:red; font-family:Arial, Helvetica, sans-serif; font-size:16px; padding:7px; font-weight:bold;\");// Not working
                List<iTextSharp.text.IElement> elements = iTextSharp.text.html.simpleparser.HTMLWorker.ParseToList(abc, styles);
                foreach (object item in elements)
                {
                    document.Add((IElement)item);
                }
                document.Close();