all their videos are like that, they seem pretty cool and they made their own window manager.

If your are on Wayland then I recommend gammastep or wlsunset.

I always go past it because I go way to fast.

I’m not a programmer but using hsl() seems so much easier and intuitive but only once you remember the hue of typical colors. Setting shades from another colours is also easy peasy with variables.

Obviously still setting a background to red/green (named) to test if a selector is correct and general testing.