On social media, the hashtag ‘Soft Goth’ (denoting style inspo that errs on the romantically crepuscular, rather than full-on Sisters of Mercy shriek wear) is a helpful starting point.

“I see a lot of brunettes wanting to go for a soft goth espresso — it’s nearly black, glossy, and striking,” says Juliana Ohlmeyer, a bicoastal colorist at Bassia Bassia. “It’s high ...