I wouldn't wear sweat pants, but it's not like you'd be the only person there not wearing a sports coat.
Upscale Attire or Casual Chic- dress shirt can be worn with trousers and no jacket & tie needed. I have worn jeans with a dressy blouse and heels. I have also worn dresses. I have seen people here for after work functions, date night, the bar scene happy hour, and Girls Night Out.
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