Implement a lint rule to highlight the deprecated @value at-rule.

[denbezrukov]

Implement no-value-at-rule.

Many tools, such as lightningcss and swc, consider the @value at-rule deprecated in favor of CSS variables.

References:

• LightningCSS Documentation: "The @value rule – superseded by standard CSS variables."
• SWC Project

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[denbezrukov]

Hi @togami2864 ,

Could you please help me with this? Do you have any thoughts or suggestions?

Thank you!

[togami2864]

Should this rule only apply to files with .module.css🤔

[denbezrukov]

Should this rule only apply to files with .module.css🤔

Hmm, interesting. We have a project with css modules but we don't write .module.css.
I think it’s better to analyze all .css files, but the rule must work only if the option is enabled.

[togami2864]

I think it’s better to analyze all .css files, but the rule must work only if the option is enabled.

Makes sense. We can ignore when the option is disabled since the parser will give a warning.
https://biomejs.dev/playground/?lineWidth=120&files.main.css=QAB2AGEAbAB1AGUAIABiAGwAdQBlADoAIAAjADAAYwA3ADcAZgA4ADsA

[rishabh3112]

@denbezrukov interested in contributing this change.