Adjustments

// Changes by fixed amounts
adjust-color($color, $blue: 5)
adjust-color($color, $lightness: -30%) // darken(\_, 30%)
adjust-color($color, $alpha: -0.4)     // fade-out(\_, .4)
adjust-color($color, $hue: 30deg)      // adjust-hue(\_, 15deg)

// Changes via percentage
scale-color($color, $lightness: 50%)

// Changes one property completely
change-color($color, $hue: 180deg)
change-color($color, $blue: 250)

Supported: $red, $green, $blue, $hue, $saturation, $lightness, $alpha