The costumes in Minari, a film by Isaac Chung, include midcentury-style button-downs and slim dresses with straight, conservative lines. These looks from the 1970s and ’80s are part of a trend in present-day South Korea called “newtro” or new retro, which is seen in popular neighborhoods of Seoul like Hongdae and Euljiro; music videos like “Dynamite,” by BTS, and “Woowa,” by Dia; and television shows like “Mr. Sunshine.”