$colors: (
  blue: #008eff,
  white: #fff,
  gray: #808080,
  black: #464646,
  orange: #ff9100,
);


@function color($key) {
  @if map-has-key($colors, $key) {
    @return map-get($colors, $key);
  }
 
  @warn "Unknown `#{$key}` in $colors.";
  @return null;
}