unitless($number) Returns whether a number has units.

rgba($red, $green, $blue, $alpha) rgba($color, $alpha)

invert($color) Returns the inverse (negative) of a color. The red, green, and blue values are inverted, while the opacity

hue($color) Returns the hue component of a color. See

adjust_color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]) Increases or decreases one

selector_extend($selector, $extendee, $extender) Returns a new version of $selector with $extendee

blue($color) Gets the blue component of a color. Calculated from HSL where necessary via

green($color) Gets the green component of a color. Calculated from HSL where necessary via

counters($args...) This function only exists as a workaround for IE7‘s

mix($color1, $color2, $weight:50%) Mixes two colors together. Specifically, takes the average of each of the RGB components