The flagged error refers to a CSS custom property (--meta-b-fcolor) used in our theme's inline CSS output. CSS custom properties (also known as CSS variables) are a valid and widely supported feature of the CSS specification (CSS Custom Properties for Cascading Variables Module Level 1). However, the W3C Nu HTML Validator may report parse errors for certain CSS variable declarations when it cannot fully resolve the value chain, particularly when values like font sizes or color tokens are chained across multiple custom properties.
The line in question is part of our theme's design token system, where variables like --meta-b-fcolor and --headline-s-fsize are defined as part of a structured typography and color configuration. These declarations are fully valid in all modern browsers and do not affect functionality or accessibility.
This is a known limitation of the Nu Validator when processing complex CSS variable stacks rather than a true standards violation. We will review this specific output to see if the declaration can be restructured to avoid triggering the validator warning, but no functional fix is required at this time.
Please let us know if you have any further questions or concerns.
https://validator.w3.org/nu/?doc=https%3A%2F%2Fserwisnaukowy.uw.edu.pl%2F
SS: --meta-b-fcolor: Parse Error.
At line 88, column 1833
re-fsize : 10px;--headline-s-f
Hello,
Thank you for sharing the validation report.
The flagged error refers to a CSS custom property (--meta-b-fcolor) used in our theme's inline CSS output. CSS custom properties (also known as CSS variables) are a valid and widely supported feature of the CSS specification (CSS Custom Properties for Cascading Variables Module Level 1). However, the W3C Nu HTML Validator may report parse errors for certain CSS variable declarations when it cannot fully resolve the value chain, particularly when values like font sizes or color tokens are chained across multiple custom properties.
The line in question is part of our theme's design token system, where variables like --meta-b-fcolor and --headline-s-fsize are defined as part of a structured typography and color configuration. These declarations are fully valid in all modern browsers and do not affect functionality or accessibility.
This is a known limitation of the Nu Validator when processing complex CSS variable stacks rather than a true standards violation. We will review this specific output to see if the declaration can be restructured to avoid triggering the validator warning, but no functional fix is required at this time.
Please let us know if you have any further questions or concerns.
Best regards,