When one thinks of a sprawling Park Avenue apartment, what comes to mind is typically muted colors, clean lines, and classic decor, but for this Upper East Side duplex, the Steven Gambrel and the designers at his firm S.R. Gambrel created a home that retains this sophistication while displaying a bevy of cheery pastel hues, geometric patterns, and unexpected accessories.

The apartment layout had barely changed since the 1930s and included a suite of servants’ bedrooms, meager closet space, a claustrophobic kitchen, and a dining room too vast for the new clients’ needs. So Brewer brought the configuration of rooms into the present while recalling the past with their moldings and profiles.