When Zara Larsson ’s on stage, all stressors fade away. Things like taxes and unanswered emails don’t exist when the Swedish pop star is twirling and twerking, singing "Midnight Sun" and "Lush Life." No matter the season, summer feels close, and all you are is happy. As Larsson’s stylist, Caterina Ospina ’s job is to ensure what the singer wears on her Midnight Sun tour enhances the feel-good energy. “ Zara loves glitter and sparkle, being super girly and sexy, but what she really needs on stage is to be free and have fun,” Ospina says over Zoom. “All the materials have to be stretchy—mesh, Lycra, and neoprene—because Zara moves 360 degrees across the stage; one second, she’s doing splits on the floor, and then she’s lifted by the dancers into the air.” Aesthetically, Larsson’s style is an amalgamation of Y2K nostalgia and island souvenir-shop kitsch; Lisa Frank-esque printed leotards and tanks airbrushed with dolphins and hot pink hibiscuses; ruffled crop tops that shimmy with her movements.…