I suggest Bootstrap responsive web design framework to design Mobile friendly websites which is compatible with all kind devices like desktop, smartphones, tablets, laptops etc.,
Columns and rows design implementation is also easy is easier compare to Foundation.
Classes naming convention easy to remember
ex. col-md-6, col-md-3 etc.,
A row will be divided into 12 columns.
We have many other features like sticky menu, accordion, quick tabs etc.,
Recently I used Foundation for front view and bootstrap for dashboard design for an Enterprise Product development. Bootstrap is easy compare to foundation.
