Perhaps you could have given examples other than Foundation that met your later assertions. Personally I've used Bootstrap for years (2 and 3), tried Foundation

Perhaps you could have given examples other than Foundation that met your later assertions. Personally I've used Bootstrap for years (2 and 3), tried Foundation back in 2.x days and it was pants in terms of default behaviour of its classes. It's always looked worse IMO, and I grew used to Bootstrap's sensible (and modular I should say, w.r.t. your 'lighter' comment) ... Sass source structure and conventions, so never been tempted to try Foundation again. I've seen a few of these 'light' flexbox-based CSS frameworks spring up, but they've always been inferior to Bootstrap 3's grid (e.g. Bulma, which has no support for multiple breakpoints in the grid out of the box).