Why don't we import css in a div?

Question

I have seen many souce codes but I have never ever come across a code which imports any css file within a div. W3C allows it,

Importing a style sheet to

Answer 1

That document you link to is a 10-year-old draft, and far from the latest. Now, if you look at the latest revision of the Style Attributes spec, which is a 2010 Candidate Recommendation that covers basically the same inline style declarations that we use every day, you won't find any @import rules mentioned anywhere anymore.

This means they took it out, presumably because it didn't make sense in retrospect, or it was difficult to implement, or some other reason entirely.