body
  color: black
  background: @color

mixin()
  background: @color

body
  color: red
  mixin()

body
  color: white
  ul
    li
      background: @color

one()
  height: 12px
  two()

two()
  color: @background-color
  font-size: @height

body
  background-color: #eee
  one()

body
  color: red
  ul
    li
      color: blue
      a
        background-color: @color

ul
  color: #ff0
  li
    color: @color - #0f0

ul
  li
    color: @color == null