Saying I have an input type="file" field. One can drop a file on this input(like in Firefox) instead of clicking "browse" and selecting the file.

Now, I want to customize it a bit, by changing the field's background color when one is about to drop a file in the input. I cannot really use :hover since it matches even when you're not drag&dropping. Is there a CSS (pseudo-class) to do that?

And is there a CSS way to style different if the file being dropped is not accepted and if it is? Say, if the field accepts only PNG files using accept attributes, I would make the field green if you're about to drop a PNG file on it, and red if that's another type of file.

Is there a CSS way to do these today? Is there a planned way to do so in CSS (like in upcoming specs/in current specs but not implements anywhere)?