A powder room is the one space where you can go all in, because it’s small, has no shower steam to fight, and you’re never in it long enough to tire of a bold color. So make it a jewel box. These walls take a deep emerald — saturated, luxurious, and unexpected — the kind of color that makes a guest stop and look twice in a room they expected to be plain.
Warm white trim and ceiling keep the edges crisp so the green reads as rich rather than cave-like, and a soft charcoal vanity grounds the scheme. The magic is in the warm brass fixtures, faucet, and mirror frame, which glow against the deep emerald and give the whole room a jewel-box shine. Use a moisture-friendly satin on the walls, keep the trim crisp, and let brass turn a tiny bathroom into the showpiece of the house.