no it isnt, why do you ask?
Just wear smart trousers and a blouse, or a smart tee. And dolly shoes. Nothing too fancy.
I haven't been to an interview there, but i can imagine it would be like lots of other chain stores. Expect lots of questions like "Tell me about a time when you worked as part of a team, what you did, how you worked from other people, and what you learned from that experience" and "Talk about the recent fashion trends at the moment".
You kind of just have to wing it. And remember, when they ask you about your negative points, just say your a perfectionist.