sass_color_blending.sass

@for $l from 0 through $color-levels
  $progress:       ($l / $color-levels) * ($n-colors - 1) + 1
  $color-a-index:  floor($progress)
  $color-b-index:  min($color-a-index + 1, $n-colors)
  $color-a:        nth($colors, $color-a-index)
  $color-b:        nth($colors, $color-b-index)
  $mix:            percentage($progress - $color-a-index)
  $bg-color:       mix($color-b, $color-a, $mix)

  .color-level-#{$l}
    background-color: $bg-color
    color: readable-text-color($bg-color)