Generated by SassMeister.com.

SassMeister-input-HTML.html

<div>Hi</div>

SassMeister-input.scss

// ----
// Sass (v3.4.13)
// Compass (v1.0.3)
// ----

$contrast-settings: (
  'light-color': #f00,
  'dark-color': #c69,
  'light-ratio': 60%
);

@mixin contrast-me($bg-color) {

  @if lightness($bg-color) < map-get($contrast-settings, 'light-ratio') {
    color: map-get($contrast-settings, 'dark-color');
  } @else {
    color: map-get($contrast-settings, 'light-color');
  }

  background-color: $bg-color;
}

div {
  padding: 2em;
  text-align: center;
  @include contrast-me(darkgreen);
}

SassMeister-output.css

div {
  padding: 2em;
  text-align: center;
  color: #c69;
  background-color: darkgreen;
}

SassMeister-rendered.html

<div>Hi</div>