Feature wall - what colour to do the other walls?

[breatheslowly]

DD's playroom has some walls painted a feature colour that we don't really like. We are going to paint them in a different strong colour (probably salsa red). It's a weird room made up of two rooms, one of which is an eaves room, so there is no line separating the lighter colour walls from the ceiling and the other room bit is more normal with to light coloured walls and a white ceiling.

So what colour should we paint the other walls/ceiling?

I'd go with the simplest answer: red and white. It's classicand smart, and you can run the white straight up from walls to ceiling.