Teen girls' wardrobe terminology: what do you call those things?

I see older teen girls wearing outfits whose parts I don’t know the names of. In order to describe them in a story, I need the right terms.

What do you call the two tops they wear when one is layered over the other so that the outer one is short and the one underneath extends several inches farther down at the waist? Are they just “tops”? What’s the term for this way of wearing them?

How about the tight (typically black) figure-hugging pants that come down a little way below the knee? What are they called, and what are they made of?—stretch fabric? cotton knit? Not the shiny ones, which I guess are Spandex, just matte black.

And is there any generally accepted expression for the hairstyle that just involves sticking a toothed spring clip into a clump of hair so that bits of it stick up and out and hang down with out evidence of any particular plan, much less an interest in neatness and smoothness?

This is not meant to be judgmental, even though these styles are very alien to me. I’m just trying to describe them so I can find out the right words for referring to them.

What else typically goes with this kind of outfit?