i = !important

/**
 * c <foreground> <border-color> <background> <foreground-important> <border-important> <background-important>
 * use 0 to omit arguments
 */
c(x, y = 0, z = 0, xi = 0, yi = 0, zi = 0)
  if (x is a 'call' || (x is a 'rgba'))
    color xi == 0 ? x : x i

  if (y is a 'call' || (y is a 'rgba'))
    border-color yi == 0 ? y : y i

  if (z is a 'call' || (z is a 'rgba'))
    background-color zi == 0 ? z : z i

bg()
  background arguments

fg()
  color arguments