@option style:legacy;

// Taken from the Ruby CHANGELOG
$themes: (
  mist (
    header #DCFAC0,
    text   #00968B,
    border #85C79C
  ),
  spring (
    header #F4FAC7,
    text   #C2454E,
    border #FFB158
  )
  // ...
);

@mixin themed-header($theme-name) {
  h1 {
    color: map-get(map-get($themes, $theme-name), header);
  }
}

div {
  @include themed-header(spring);
}