When the Italian jewelry designer Bea Bongiasca, 34, founded her namesake brand in 2014, she set out to create a world where whimsy reigns. Her sculptural, irreverent collections have included curling bright yellow, orange and purple enameled rings that resemble jewel-encrusted vines, and knotlike silver earrings inspired by taralli, the savory biscuits from Puglia, where her grandmother was born. And while it’s natural for an artist’s private space to become an extension of their work, that’s especially true of Bongiasca’s 800-square-foot Milan apartment. “It’s designed like a box,” she says of the compact two-story loft awash in acid green and hot pink. “Like a jewelry box, I guess.”

On a crisp winter day, Bongiasca swishes down her home’s Barbie pink staircase wearing a voluminous pair of floral-print cargo pants and a matching crop top, with her British longhair cat, Fat Momo, trailing at her heels. Bongiasca was born not far from her apartment, which overlooks the ancient walnut and oak trees of Milan’s Sempione Park. She’s spent most of her life in the city, save for a few years in London, where she studied jewelry design at Central Saint Martins.

Her building, with its gridlike gray stone facade, was designed in 1965 by the architect and urban planner Giulio Minoletti, best known for his public and industrial projects across and outside Milan. Compared to the spacious, family-oriented apartment blocks common in the neighborhood, it has an unusual composition: four floors of nearly identical studios. The design was inspired by the two-story lofts that make up the modernist architect Le Corbusier’s 1952 Unité d’Habitation in Marseille, France, and was commissioned by Alitalia, the now-defunct Italian airline, to provide homes for its pilots. It was known as a casa albergo, or “house hotel” — a warren of bachelor pads in the heart of Milan.

“Since the building was designed in the 1960s, we wanted to create a homage to that era,” Bongiasca says of the apartment’s interior, which centers on a spacious conversation pit — composed of modular dark red cubes that can be extracted and used as stools — installed beneath the chartreuse living room’s 13-foot ceiling. The space was designed by the architect Massimiliano Locatelli, a longtime friend of Bongiasca’s mother who also designed her childhood bedroom and later her boutique on Via Solferino, both in shades of cotton candy pink.