> you need two levels of grouping Not necessarily. I can define form { flow:row(label, input select textarea); } to have typical form's two columns layou

> you need two levels of grouping Not necessarily. I can define form { flow:row(label, input select textarea); } to have typical form's two columns layout with all <label>s go to first column and input, select and textarea go to second. All non-matching elements are replaced as if they span full rows (like <caption> in tables). People at trying to simulate these things by using float and clear. Ugly, non-reliable, etc.