s-grid-functions.styl

rem-calc(value)
    u = unit(value);
    if (u is 'rem') {
        return unit(value, u);
    } else {
        return unit(value / base-font-size, 'rem')
    }

grid(direction = 'row', cells-align = 'top', justify = '')
    display flex
    flex-wrap wrap
    if cells-align is 'top'
        align-items flex-start
    if cells-align is 'bottom'
        align-items flex-end
    if cells-align is 'center'
        align-items center
    if cells-align is 'stretch'
        align-items stretch
    if direction is 'row'
        flex-direction row
    if direction is 'row-reverse'
        flex-direction row-reverse
    if direction is 'column'
        flex-direction column
    if direction is 'column-reverse'
        flex-direction column-reverse
    if justify is 'center'
        justify-content center
    if justify is 'start'
        justify-content flex-start
    if justify is 'end'
        justify-content flex-end

cell(i = 1, cols = columns, align = '', g = gutter)
    if g is not 0
        flex-basis: s('calc(100% * %s - %s)', i / cols, rem-calc(g))
    else
        flex-basis: s('calc(100% * %s)', i / cols)
    min-width 0 // FF adjustment for responsive images
    if g is not 0
        margin: rem-calc(g / 2)
    if align is 'top'
        align-self flex-start
    if align is 'bottom'
        align-self flex-end
    if align is 'center'
        align-self center

cell-offset(i = 1, cols = columns, g = gutter)
    if g is not 0
        margin-left: s('calc(100% * %s + (%s / 2))', i / cols, rem-calc(g)) !important
    else
        margin-left: s('calc(100% * %s)', i / cols) !important

center(value, pad = null)
    margin-left auto
    margin-right auto
    width 100%
    u = unit(value)
    if (u is 'rem' or u is '%')
        max-width unit(value, u)
    else
        max-width rem-calc(value)
    if (pad is null)
        return
    else
        p = unit(pad)
        if (p is 'rem' or p is '%')
          padding-left  unit(pad, p)
          padding-right  unit(pad, p)
        else
          padding-left rem-calc(pad)
          padding-right rem-calc(pad)

stack()
    cell(1, 1)