And HTML is a markup language for hypertext, a document rather than an application. But it turns out that we're using it and CSS and JavaScript to build full b

And HTML is a markup language for hypertext, a document rather than an application. But it turns out that we're using it and CSS and JavaScript to build full blown applications. So, because we're trying to solve problems with applications rather than documents, we have to map the problems of application programming onto it. So, to build an application, we run into problems CSS wasn't designed to solve (being a not-programming language.) Whether it is or isn't a programming language is irrelevant - to solve our problems (writing applications), we have to treat it as if it is.