-
Well, Barney obviously would wear a suit during phase 1, but I'd recommend something more comfortable. Some nice shirt will be way more elegant than the average, but if you insist to be elegant, than do it. But keep in mind that during ph1, you have to sit in front of a computer all the day, and a suit may be not the perfect choice.
Oh, and answering your question: no, there is no dress code.