// Return a lighter color
// 0% is the same color, 100% is white
@function tint($color, $percent, $alpha: 1) {
  @return rgba(mix(white, $color, $percent), $alpha);
}

// Return a darker color
// 0% is the same color, 100% is black
@function shade($color, $percent, $alpha: 1) {
  @return rgba(mix(black, $color, $percent), $alpha);
}

// Return an intensity of white
// 0% is black, 100% is white
@function white($intensity: 100%, $alpha: 1) {
  @return rgba(tint(black, $intensity), $alpha);
}

// Return an intensity of black
// 0% is black, 100% is black
@function black($intensity: 100%, $alpha: 1) {
  @return rgba(shade(white, $intensity), $alpha);
}

// Return a tint of gray
// 0% is black, 100% is white
@function gray($intensity: 50%, $alpha: 1) {
  @return rgba(mix(white, black, $intensity), $alpha);
}