accessibleAccent

The nearest colour to accent that reaches target against the text colour Metro would put on it, found by walking towards black or white.

Nine of the twenty Windows Phone accents fall below AA at their authentic text colour, cyan — the phone's own default — among them at 2.90:1. This is what the opt-in palette applies, and it is computed rather than hand-picked so that a caller's own accent gets the same treatment.

The hue is preserved; only the distance to black or white changes.