She redecorated her boyfriend’s apartment. TikTok hated it.

Shortly after Emma Ganzarain moved into her boyfriend’s apartment in Oslo, the couple started working on a redesign. They added light-colored herringbone floors, with radiant heating to combat the Norwegian chill, and taupe kitchen cabinets. In the living room, the couple swapped a purple lamp for a white one and replaced a maroon armchair with a similarly sized chair in off-white.

As the work neared completion, Ms. Ganzarain, 26, posted a few before-and-after posts photos on TikTok. “All men need a woman in their lives,” she wrote in the caption.

The reaction was not what she expected.

Her post has been viewed almost 8 million times since it was published earlier this month. It has also attracted more than 55,000 comments, most of which are negative. Many people have accused Ms. Ganzarain, who had about 3,000 TikTok followers at the time of the post, of ruining her friend’s space and replacing its warmth and character with a more sterile look.

“The former is better,” one commenter wrote. “After is very clinical and cold.” The person then noticed the “Patrick Bateman vibes” of the renovated apartment, a reference to the serial killer protagonist from “American Psycho.”

In an interview, Ms. Ganzarain, who works in resource management, explained her aesthetic: “I like the basic neutral palette. Beige, white, brown. Earth colors.” She said her boyfriend lived alone before she moved in, adding that the apartment was old and needed some upgrades.

Some commenters went beyond their criticism of the redesign and accused Ms. Ganzarain of controlling her partner (who was very closely involved in the process, she noted). Others sent her death and rape threats, she said.

Several of Ms. Ganzarain’s detractors mentioned the phrase “sad beige,” an Internet term used to describe a minimalist style with an emphasis on neutral tones. Hayley DeRoche, a librarian in Petersburg, Virginia, passing by @sadbeige on TikTok, helped popularize the term through numerous posts satirizing the trend.

“It’s a very specific aesthetic that incorporates neutral colors to an almost absurd, monochromatic degree,” says Ms. DeRoche, 37. A typical “sad beige” room, she added, has “a lot of eggshells, a lot of cream, a lot of oatmeal, cardboard, biscotti, sand.” Referring to the Kardashians, who are famous fans, Ms. DeRoche added that the sleek, almost colorless look can be an effective sign of wealth.

Ms. DeRoche added that she disagrees with those who use the term “sad beige” as a weapon to attack an individual poster. She also theorized that the strong response to Ms. Ganzarain’s post could signal a larger shift in home furnishings, from uncluttered minimalism to something cozier and less polished.

Emily Rayna, one interior designer in New Hampshire agreed that the era of neutrals was coming to an end. “People are trending toward maximalism, which makes me happy,” she said, “but we’ll probably have a setback from that at some point in the future as well.”

Ms Ganzarain said she believed the TikTok backlash was partly because she posted the before and after photos before the redesign was complete. “We didn’t even have lights in the kitchen!” she said. “The sink was not installed.” Still, she said, she’s enjoyed some of the conversations she’s had with people online, discussing everything from light temperature to pillows.

As for her boyfriend, who declined to be named for this article, he weighed in just over a week after his apartment became TikTok famous.

“Did you really like how we changed the apartment?” Mrs. Ganzarain asks in one video which shows her pointing a toy gun at his head.

“Mhmm,” he replies, nodding toward the camera with a blank expression.

“Blink twice if you need saving,” reads one top comment.