The 8-digit hexadecimal RGBA syntax is a more standard way to represent colors than the rgba() color function, which is CSS-specific.
The 8-digit hex notation is valid CSS as of the CSS Level 4 spec: https://www.w3.org/TR/css-color-4/#hex-notation
Additionally, the CSS rgba() comma-separated color function is considered *legacy color syntax* as per the CSS Level 4 spec: https://www.w3.org/TR/css-color-4/#legacy-color-syntax
Sass has built-in support for CSS Level 4 color notations: https://sass-lang.com/documentation/values/colors/
The 8-digit hexadecimal RGBA is a drop-in replacement for rgba() values in both CSS and SCSS, so this is functionally compatible if the file is used directly.
BREAKING CHANGE: drops CSS rgba() values in all output formats. It's a soft breaking change for CSS and SCSS outputs, but a hard one for JSON.
BREAKING CHANGE: CSS variables (color) are no longer lowercase. Since CSS custom property names are case sensitive, this would break existing consumers.
zod unions are exclusive, so the UserConfig type couldn't be kept as a union either for having at least a colors, typographies or pages output.
This check has been moved to a runtime zod refine custom validation.
