Yuzu’s pink and blue came from when you pendulm summon…
Serena’s palette came from when you perform a fusion summon…
And now Rin’s colors came from when you perform a synchro summon…
… So, gee, I wonder where Ruri will get her color scheme from?
There was an interview with I think one of the character designers for ArcV who said the color schemes of the Yuya-lookalikes was based on the summons/card colors so
Yuya - Red and Green (Pendulum) Yuto - Black and purple (xyz) Yuri - Purple and pink (fusion) But for Yugo it was white but they thought white wouldn’t be a good hair color so it was yellow/blue and his outfit and d-wheel are white.