When Emily Peterson purchased her seaside cottage in Cape Neddick, Maine, she knew its coastal hues had to go. “The second we walked through this house, I had this vision that I wanted it to be dark,” said Ms. Peterson, who bought the 1770s home nearly two years ago. “It’s been here for so many years and I just wanted to bring life back into it.”

And in this case, that meant going back to its historical roots with moodier colors.

So Ms. Peterson, who shares the cottage with her husband and two young children, painted over the butter yellow and powder-blue walls with dark greens and deep blues.

Bright, vibrant spaces have enjoyed their time in the sun — after all, last summer’s Barbiecore moment even extended to homes — but there’s growing interest in a dark interior aesthetic. On TikTok, videos highlighting this style often rack up thousands of likes. And on the home-decorating website Houzz, there’s been surge in searches related to dark and moody décor — for example, “moody bedroom” searches are up 142 percent.

“The popularity of dark and moody décor is likely a reaction to the bright whites and light grays that have dominated interiors in recent years,” said Mitchell Parker, Houzz’s senior editor. “Many homeowners are looking for something different.”

That was the case for Ms. Peterson, a 33-year-old artist whose previous home had light gray walls. Now, each room in her cottage has its own deep shade: Blackish-green walls — painted using Andiron by Sherwin-Williams — in the living room set a backdrop for a green velvet couch and a gallery wall of vintage oil paintings.