It depends on the day you're joining! We made a full Outfit Guide here — check it out for links, color themes, and shopping suggestions. https://docs.google.com/document/d/1awFU_eEth2cgGzZ3Q3pdDR67GsAkIoAn/edit?tab=t.0
Nope! There's no requirement. Traditional outfits are encouraged for those who want to wear them, but are totally optional.