absCenter($position = absolute)
  $w = @width
  $h = @height
  position: $position
  top: 50%
  left: 50%
  if !$w and !$h
    transform: translate(-50%, -50%)
  if $w and $h
    margin-left: -($w/2)
    margin-top: -($h/2)
  else if $w
    margin-left: -($w/2)
    transform: translateY(-50%)
  else if $h
    margin-top: -($h/2)
    transform: translateX(-50%)

absCenterX($position = absolute)
  $w = @width
  position: $position
  left: 50%
  if $w
    margin-left: -($w/2)
  else
    transform: translateX(-50%)

absCenterY($position = absolute)
  $h = @height
  position: $position
  top: 50%
  if $h
    margin-top: -($h/2)
  else
    transform: translateY(-50%)

absCover($position = absolute)
  position: $position
  top: 0
  bottom: 0
  left: 0
  right: 0