I’m just going to throw this out there, in my own headcanon for Touhou, Reimu’s hair glows purple when she uses her Float ability at full power, at which point she simply “floats” away from reality, such as when she uses the spellcard “Innate Dream”.
Something that really tickles me during the livestream and event: what are those extra arm sleeves on her jacket are for? There's no hole leading to them, and based on the shoulder part it's certainly not something detachable or something with heavy load like robotic arms. Nor it is hole for legs.
