a neat clip studio paint (and manga studio) trick!
fiddling with “color margin” in the brush settings will change how well it goes over the lineart. the lower it is, there may be slight gaps between your colors and your lines. fiddle with it until you get what you like!
while this trick makes it so you don’t need to be as precise laying in your colors, you still need to be a bit gentle with the brush. don’t go too crazy.
you can make as many layers for your colors as you want (i just used one for this tutorial)! however i’m fairly sure you can only make one reference layer at a time.
i’m sure you can use this trick for other purposes (to help with shading, etc), so this is just a basic tutorial to show how it works!