ghost-arrow($size = 16px, $color = red, $width = 1px, $direction = right)
  content: ''
  display: block
  width: $size
  height: $size
  border-width: 0 $width $width 0
  border-style: solid
  border-color: $color
  if $direction == top
    transform: rotate(-135deg)
  else if $direction == left
    transform: rotate(135deg)
  else if $direction == bottom
    transform: rotate(45deg)
  else if $direction == right
    transform: rotate(-45deg)