Warn (never block) when a CUSTOM categorical palette departs from
the safe defaults: low contrast against the canvas background, plus
a CVD note since the named palettes are colorblind-safe and a custom
array may not be. The createTheme posture, applied to encodings.
Warn (never block) when a CUSTOM categorical palette departs from the safe defaults: low contrast against the canvas background, plus a CVD note since the named palettes are colorblind-safe and a custom array may not be. The createTheme posture, applied to encodings.