@function values($exclude-hardcoded-values: false) {
  @return (
    'dragged-state-layer-opacity': if($exclude-hardcoded-values, null, 0.16),
    'focus-state-layer-opacity': if($exclude-hardcoded-values, null, 0.12),
    'hover-state-layer-opacity': if($exclude-hardcoded-values, null, 0.08),
    'pressed-state-layer-opacity': if($exclude-hardcoded-values, null, 0.12)
  );
}