I learned from my mom that black and white always works, period. Whether in fashion or interiors, whether it's a traditional or modern space, there's nothing like a black and white palette that says timeless. Black can add a bit of edginess to any room and help a room from becoming too sweet. No matter how traditional, any piece of furniture painted black is transformed instantly and can work in just about any space. I apply the same concept to architectural details such as your stairs.
The graphic quality of black and white can make a space more conducive to incorporating modern furnishings and bright colors into the mix.