When it was done in anime/manga mainly with female characters-
Blue(usually dark) - Mature motherly adult female.
Rainbow - That was never a thing or maybe done with a character's highlights but didn't change the other color's meaning.
Purple(usually dark to the point of being black) - Reserved for young female characters. Indicates immaculate kindness, manners, and traditions and they grow up to be like the Blue haired characters.
Green - Usually a young female character that lost everything to tragedy but still retains her childhood innocence. Tends to trigger other male character's Big Brother/Papa Wolf instincts.
Pink - Loves living life to the fullest but tends to be naive about plot issues or is a cuckoocloudlander to one degree or another.
Controversial take from a conservative to my fellow conservatives but maybe we need to get rid of that statue. Notice that before the statue, immigration to the US was very limited and very strict to enter let alone becoming a legal immigrant and later a full citizen.
Yet after that statue was put up those strict laws, regulations, and standards were gradually eroded and gotten rid of.
