The dominant aesthetics at Parookaville are rave wear, EDM festival wear, neon and full costume. That is the visual language of the site, the stages, the merch, the crowd photos, and outfits that speak it look intentional rather than borrowed.
This is a costume festival, and that changes the maths: turning up in normal clothes is the conspicuous choice. Budget for one full look rather than three half-hearted ones, and make sure you can walk, dance and queue in it for eight hours.
What people actually wear: one good layer over a light base, because the temperature halves after sunset; the same jacket every day, because it lives in the tent and does everything; something identifiable, a colour, a hat, a flag, so your group can find you in a crowd of that size.