indeed, i found most of the employees dress casually when i went to the interview. only the manager was in suit and tie and he just came back from a ceremony. it seems that their dress code is not that formal. probably, i should put on car key and simple shirt.
well, if you want to look professional, serious and more conservative, a blue dress, white shirt and not-too-high shoes would be the best choice. but sometimes, very formal clothes will keep you at a distance from your colleagues. it depends on the company’s dress code.