For what felt like forever, vintage jeans were the go-to model-off-duty bottoms, always paired with plain white T-shirts and ribbed tank tops. But as of late, a new pant style appears to have taken over among fashion people, and it just got the ultimate placement.Ahead of her celeb-packed 27th birthday party at Zero Bond in NYC, Gigi Hadid was spotted on a walk with her mom wearing low-slung baggy trousers styled with fellow model Hailey Bieber’s go-to platform Uggs, a cropped quarter-zip sweatshirt from Kith, and the Loro Piana Pouch bag.