Not medical. This is html5 + CSS3. It's how you make striking web content today (unless you're Daesh, in which case you just upload a video of someone sawing another person's head off).
Compared to previous languages, html5 and CSS3 are pretty easy - but inseparable. You want to build great web pages? That's what you do. Cascading Style System version 3 (CSS3) works almost seamlessly with the html5 platform.
It looks as though a cease-fire agreement has been reached.