zurb foundation 3中的固定宽度列

How do i implement a fixed column grid in zurb foundation 3? Currently, foundation's grid is fluid and are based on percentages. I want to implement something similar to the bootstrap (non-fluid) grid whereby there are only 4 posibilites on how your grid is displayed (well at least until it drops down to mobile, which is fluid) How do i implement a fixed column grid in zurb