Inactive Track Color for Sliders

I notice that only the active track color is currently customizable - being able to control the inactive track color would be amazing and open up lots of new possibilities... for example, I really like having the Touch Bar completely black, but still having areas I can touch for functionality. Being able to turn the inactive track color black, would allow the slider widget to be used like this... in that vein, being able to turn off the reactive flashes when touching a button would also be great. Thanks! Love the app!