W2c_sm

Width 2 of 4 columns on `sm` and all subsequent breakpoints.

W2c_sm W4c_md

2 of 4 columns on `sm`
4 of 12 on `md` and all subsequent breakpoints.

W1c W-a_md W10c_lg

1 of 2 columns on `xs` and `sm`
auto on `md`
10 of 12 spans on `lg` and all subsequent breakpoints.