Dress code for undergrad lab interview?

I'm currently in undergrad and just scored an interview for a lab position. They said in the email that dress is casual and to keep in mind that it will be in a lab setting. I'm not really sure what to wear (I'm a female), and if casual means like khakis or a nice pair of jeans. It's also winter so I don't really want to freeze my feet off in flats, but all I really have for shoes is black high tops and heeled dress boots. Advice for the interview itself too would be great, they said it's with the staff and I've never had an interview with multiple people.

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