You're trying to mix a color, but you're receiving this warning.
Explanation
Motion doesn't support named colors. JS animation libraries that support named colors are importing a list of names and colors, and this adds a lot of weight to the bundlesize for not much use.
In the future, thanks to Motion's hybrid engine that uses WAAPI for select animations, it might be possible to support this without the extra bundlesize.
Solution
Convert the named color to RGBA/Hex/HSLA.