Madam Malkin's Robes for All Occasions
A regular stop for Hogwarts school uniforms, Madam Malkin also
carries robes that are spangled, self-ironing, beautifying, slimming,
fattening, lengthening and temperature-adjusting.
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Hogwarts robes
While the Harry Potter books imply that wizards do not understand
Muggle fashion (one famously imitates a Muggle by wearing a kilt and a poncho),
witches and wizards in the films generally wear the same clothes
as those outside the magical world. Students at private schools in
Britain sometimes do wear academic robes, however, so the uniforms retain this style.