does't apply bootstrap effect on generated PDF file from HTML template using ITextRenderer in Spring boot application

Question

I have designed HTML template using Bootstrap and I am generating PDF file using following code

OutputStream outputStream = new FileOutputStream("message.pdf");
        ITextRenderer renderer = new ITextRenderer();
        renderer.setDocumentFromString(html);
        renderer.layout();
        renderer.createPDF(outputStream);
        outputStream.close();

But I am not getting bootstrap effect in generated PDF file

How can I apply Bootstrap effect in Generated PDF or How can I generate PDF file from Thymeleaf HTML tamplate ?