You look nice

Hello! I know this has been asked before but I am wondering if there is a French cultural equivalent to this English phrase. This phrase in English is totally friendly and just a comment that someone has dressed up nice. A friend or acquaintance could use it without it coming across as flirtatious. It's not a comment on personal beauty or form, but specifically a comment about clothing or the way someone has done their hair/make-up.

I think that "Tu es élégant(e)" would fit the bill, although you always run the risk of this compliment being taken as a comment of the person's usually more shabby appearance. Tread carefully...

Tu es ravissante...

You could avoid any faux pas by saying that you like what she's wearing / her hairdo and that it suits her:
J'aime bien / beaucoup ta tenue (ta coiffure), ça te va bien.