RYB vs RGB color wheel
The artist's paint wheel and the screen-light wheel order hues differently, so they give different answers for which color is opposite.
See it
What it is
The RYB wheel is the traditional artist model built around red, yellow, and blue paint. Its familiar opposite pairs are red and green, yellow and violet, blue and orange. The RGB wheel models colored light and underlies CSS HSL hue angles: red faces cyan, green faces magenta, and blue faces yellow.
Johannes Itten's 12-part RYB circle shaped Bauhaus color teaching and still dominates art classrooms. Reach for that wheel when discussing painting traditions or palettes chosen by eye. Reach for the RGB wheel when generating CSS colors, rotating hue in code, or reasoning about light from screens.
Gotcha: RYB is not a simple relabeling of evenly spaced CSS angles. Adding 180 degrees to hsl() always finds the RGB/HSL opposite, not the artist's complement. Name the wheel before giving an angle or calling two hues complementary, especially when translating an art direction into code.
Ask AI for it
Create a switchable RYB versus RGB color wheel with CSS conic-gradient(). For RGB, use the CSS HSL order red, yellow, green, cyan, blue, magenta. For RYB, author separate stops in the traditional order red, orange, yellow, green, blue, violet instead of calculating them with hsl(). Draw a diameter through the selected hue, label the opposite on each wheel, and demonstrate that blue maps to orange in RYB but yellow in RGB.