private static LazyValue newLazyColorFunction( String uiKey, ColorFunction function ) {
		return (LazyValue) t -> {
			Object color = lazyUIManagerGet( uiKey );
			return (color instanceof Color)
				? new ColorUIResource( ColorFunctions.applyFunctions( (Color) color, function ) )
				: null;
		};
	}
Syntax: over(foreground,background)
  - foreground: a foreground color (e.g. #f00) or a color function;
                the alpha of this color is used as weight to mix the two colors
  - background: a background color (e.g. #f00) or a color function
flatlaf-core/src/main/java/com/formdev/flatlaf/UIDefaultsLoader.java