.icon
  display: inline-block
  vertical-align: middle
  line-height: inherit
  font-size: 1em
  width: 1em
  height: 1em
  &:not(:last-child)
    margin-{$dir-end}: $margin

  // generate color modifiers
  for color in $modifiers-color
    $color = lookup('$' + color)
    &.is-{color}
      _icon-color: $color

  // generate size modifiers
  for size in $modifiers-size
    $size = lookup('$size-' + size)
    &.is-{size}
      width: $size
      height: $size