According to TikTok, the hottest style right now is “coastal grandma,” inspired by relaxed, oceanside minimalism and lots of linen. Before that, it was “indie sleaze” — a hipster look of plaid shirts, beanies and leggings under dresses. And before that, it was “twee,” a retro-feminine style heavy on Peter Pan collar shirts and colourful tights. Tomorrow, it might be “royalcore,” “night luxe” or “Miley Stewart…