See : https://github.com/w3c/csswg-drafts/issues/8943 Various implementation bugs exist in Safari for parts of css-color-4 and css-color-5. The specification has also gone through substantial changes since implementation was started. Currently WPT tests do not reflect the specification. The specification itself still has a few details that require clarification and resolutions. Authors are learning incorrect things about these features because all browsers shipped "something" for css-color-4 and css-color-5 and because they all shipped different things. Ideally the issues are resolved as quickly as possible and roughly by all vendors at the same time. These features are part of interop 2023.
A codepen : https://codepen.io/romainmenke/pen/GRwWpMN This should be a lighter shade of blue, instead it shows either green or pink, depending on the browser engine
To clarify, the example is simply an example of one of the many compat issues. It is not the sole issue.
<rdar://problem/111753247>