that's what I mean. how does this effect fashion?
Or, if I can be blunt- the difference between the american idea of being edgy and contercultural and the chinese idea of being edgey and countercultural is that the government in america will not run you over with tanks if you organize a public sit down. (However, make no mistake, the government in america will eliminate dissidents of enough threat in similar ways to china- see chelsea manning or the black panther movement.)
Of course it affects behavior in public, as well as clothing and dress. You can't openly support movements- including the wearing of logos, brans, slogans, sayings, etc.
"do Chinese millennials use hair colors that don't occur in nature as often"
I'm pretty sure dyed hair is still considered popular and fashionable in east asian cultures, given the pop bands coming out of there!
This isn't true. There have been several documentaries covering people trying to drive change in China that the west has documented. (Hooligan Sparrow, Ai WeiWei: Never Sorry, The Ivory Game, etc. just on Netflix alone) The problem is, these people are regularly disappeared in China and their lives are put at risk by doing this work.
In truth, most people know the chinese government, especially Xi, is behaving to preserve control first and foremost. That this benefits the chinese economically is a side effect- but now that effect is waning.