>>280771815
I think it's kind of like how the upper escalations of the Roman Catholic church still dress like it's the middle ages even now. Their clothes froze at one point in time and they kept wearing them because they're basically uniforms of office. So the imperial court is still dressing like it's the Heian period because that was the last time they were relevant.

It makes it pretty noticeable that once the imperial court becomes actually relevant again they instantly update in fashion to modern times.