Hi there Mitzicat, the daytime wear is the same as you would expect to see on any cruiseline, shorts, tees, slacks, skirts, pumps etc.
Shorts aren't really the thing to wear if you are eating in the MDR at lunchtime, but for the excellent self-service stations they are more than acceptable - well unless it's snowing outside
As for the evenings, yes pretty formal most nights. If you are booked & take a look at the Voyage Personalizer at the bottom of the Cunard homepage, there is somewhere that tells you how many formal, semi formal and smart casual nights you will have - though I can never find it straight away
Hope this helps,