For my office in Silicon Valley, we'd need to add a level 6 and possibly 7.
Men: company logo t-shirts, shorts, gym shoes, jorts, logo polo shirts
Women: jeans, shorts, t-shirts
Men: sweatpants, flip-flops, oversized t-shirts, athletic shorts, socks with sandals, shorts with long sleeve shirts
women: yoga pants, flip-flops, athletic tops, workout wear, short skirts, low cut tops
The CEO dresses somewhere between 3-5 in the boardroom.