$dp-fonts: (
  'primary': sans-serif
) !default;

@function dp-font($name) {
  @if map-has-key($dp-fonts, $name) {
    @return map-get($dp-fonts, $name);
  }

  @error "#{$name} is not a valid font name";
}

html {
  font-family: dp-font('primary');
  font-size: $dp-base-size;
  line-height: $dp-base-line-height;
}