I can’t tell if that’s just the fashion at the moment, or an extreme vague allusion to school uniforms.
It’s so broad and vague a uniform reference (if that’s what it’s intended to be at all), it could be referencing American private school uniforms, British school uniforms, Korean or Japanese school uniforms… or even (some) Chinese school uniforms (apparently the plaid skirts, ties and sweater-vests have made their way to China). Or all of the above.
