Good luck with that - you'd need to have a fully standards-compliant HTML/CSS/JS engine in order to get the same output, and at that point that's literally just

Good luck with that - you'd need to have a fully standards-compliant HTML/CSS/JS engine in order to get the same output, and at that point that's literally just a browser (and would require a massive investment of time for maintenance). A driver for an existing browser is the only reasonable option for the foreseeable future, with how complex modern web development has become.