Invalid elements

Invalid @property declaration  

Reports a missing required syntax, inherits, or initial-value property in a declaration of a custom property.

Invalid @property name  

Reports an invalid custom property name.

Invalid function  

Reports an unknown CSS function or an incorrect function parameter.

Invalid media feature  

Reports an unknown CSS media feature or an incorrect media feature value.

Invalid nested selector  

Reports a nested selector starting with an identifier or a functional notation.

Invalid property value  

Reports an incorrect CSS property value.

Invalid pseudo-selector  

Reports an incorrect CSS pseudo-class pseudo-element.

Invalid type selector  

Reports a CSS type selector that matches an unknown HTML element.

Misplaced @import  

Reports a misplaced @import statement.

Misplaced or incorrect @charset  

Reports a misplaced @charset at-rule or an incorrect charset value.

Negative property value  

Reports a negative value of a CSS property that is not expected to be less than zero, for example, object width or height.

Unknown at-rule  

Reports an unknown CSS at-rule.

Unknown property  

Reports an unknown CSS property or a property used in a wrong context.

Unknown unit  

Reports an unknown unit.

Unresolved class in 'composes' rule  

Reports a CSS class reference in the 'composes' rule that cannot be resolved to any valid target.

Unresolved custom property  

Reports an unresolved reference to a custom property among the arguments of the var() function.

Unresolved file reference  

Reports an unresolved file reference, for example, an incorrect path in an @import statement.