how to import stylesheet in pdf when i create pdf in vb.net

Dim builder As New PDFBuilder.HtmlToPdfBuilder(PageSize.LETTER)
            Dim first As PDFBuilder.HtmlPdfPage = builder.AddPage()
            Dim second As PDFBuilder.HtmlPdfPage = builder.AddPage()
            first.AppendHtml(question)
             builder.ImportStylesheet("D:\\multiply.css")
Dim files As Byte() = builder.RenderPdf()
System.IO.File.WriteAllBytes("D:\\Multiplicationtabledisp.pdf", files)
Dim strFilename As String = "D:\\Multiplicationtabledisp.pdf"
       Response.ClearContent()
in the about code , i didnt get proper styles like width, height and all  in pdf page when i create the html string to pdf format...
guess importsylsheet ...