Just a quick mention of Celebrity's web site:
Note that T-shirts, swimsuits, robes, bare feet, tank tops, baseball caps and pool wear are not allowed in the main restaurant or specialty restaurants at any time. Shorts and flip-flops are not allowed in the evening hours. The appropriate dress code will be enforced at all restaurants. Additionally, you are asked to follow the "Smart Casual & Above" dress code in the Celebrity Theater for all evening performances.