//YIQ Implementation
@function yiq($color) {
  $red  : red($color);
  $green: green($color);
  $blue : blue($color);

  @return (($red*.299)+($green*.587)+($blue*.114));
}

@function color-contrast($background, $dark:#000, $light:#fff) {
  @if yiq($background) >= 128 {
    @return $dark;
  } @else {
    @return $light;
  }
}