fr(selector, name, i = '')
  unquote(replace(unquote('<i>'), unquote(i), replace(unquote('<name>'), unquote(name), unquote(selector))))

fe(selector, name, noProc, i = '')
  if noProc
    return fr(selector, name, i)
  return unquote(join(',', fr(selector, '', i) fr(selector, name, i)))

fg($name, $size)
  $noProcNotZero = $size > 0
  @media (min-width $size)
    {fe('.col<name>', $name, $noProcNotZero)}
      &, &-auto, &-grow
        .row > &, .flex > &
          width auto
          min-width 0
          max-width 100%
        .column > &, .flex > &
          height auto
          min-height 0
          max-height 100%
      &
        flex 10**4 1 0%
      &-auto
        flex 0 0 auto
      &-grow
        flex 1 0 auto

    for $i in (0..$flex-cols)
      $ic = s('%s', $i)
      {fe('.col<name>-<i>', $name, $noProcNotZero, $ic)}
        @extend .col{$name}-auto
      .row
        {fe('> .col<name>-<i>', $name, $noProcNotZero, $ic)}
          height auto
          width (round($i / $flex-cols * 100, 4))%
        if $i != 0 || $name != ''
          {fe('> .offset<name>-<i>', $name, $noProcNotZero, $ic)}
            margin-left (round($i / $flex-cols * 100, 4))%
      .column
        {fe('> .col<name>-<i>', $name, $noProcNotZero, $ic)}
          height (round($i / $flex-cols * 100, 4))%
          width auto

.row, .column, .flex
  display flex
  flex-wrap wrap
  &.inline
    display inline-flex

.row.reverse
  flex-direction row-reverse

.column
  flex-direction column
  &.reverse
    flex-direction column-reverse

.wrap
  flex-wrap wrap
.no-wrap
  flex-wrap nowrap
.reverse-wrap
  flex-wrap wrap-reverse

.order-
  &first
    order -10000
  &last
    order 10000
  &none
    order 0

.justify-
  &start
    justify-content flex-start
  &end
    justify-content flex-end
  &center
    justify-content center
  &between
    justify-content space-between
  &around
    justify-content space-around

.items-
  &start
    align-items flex-start
  &end
    align-items flex-end
  &center
    align-items center
  &baseline
    align-items baseline
  &stretch
    align-items stretch

.content-
  &start
    align-content flex-start
  &end
    align-content flex-end
  &center
    align-content center
  &stretch
    align-content stretch
  &between
    align-content space-between
  &around
    align-content space-around

.self-
  &start
    align-self flex-start
  &end
    align-self flex-end
  &center
    align-self center
  &baseline
    align-self baseline
  &stretch
    align-self stretch

.flex-center
  @extend .items-center
  @extend .justify-center

for $name, $size in $flex-gutter
  .gutter-
    &x-{$name}
      margin-left (- $size)
      > div
        padding-left $size
    &y-{$name}
      margin-top (- $size)
      > div
        padding-top $size
    &{$name}
      @extends .gutter-x-{$name}, .gutter-y-{$name}
      > div
        @extends .gutter-x-{$name} > div, .gutter-y-{$name} > div

for $name, $size in $sizes
  fg(s('-%s', unquote($name)), $size)