Changing unlit floor grid colours

[Maq]

I've recently done my regular dip back into Angband and it's my first time with version 4.x.y. The unlit floor grids in the dungeon are a "." character and they're pretty indistinguishable from lit floor. Apart from anything else it makes LoS difficult to determine. How would I go about dimming the colour? Or is there a "remember lit grid" setting somewhere I'm missing?

e2a: Found it under the knowledge -> features menu. Can't seem to get it to distinguish between Dark and Lit reliably though.

[DavidMedley]

That menu is VERY touchy. I get LOS squares to show orange, but if I do anything other than that via the most direct path it usually breaks.