CSS --* Property Reference

The CSS --* property is a standard property in CSS Custom Properties for Cascading Variables. Review its formal syntax, computed behavior, and practical declarations.

Updated 2026-08-12

--* overview

The CSS --* property is a standard property in CSS Custom Properties for Cascading Variables. Review its formal syntax, computed behavior, and practical declarations.

The computed value normally inherits from the parent element when no declaration wins the cascade.

Syntax and formal definition

--* formal syntax

Field	Value
Formal syntax	<declaration-value>
Initial value	seeProse
Applies to	allElements
Inherited	Yes
Percentages	no
Computed value	asSpecifiedWithVarsSubstituted
Animation type	discrete
Media	all
Specification group	CSS Custom Properties for Cascading Variables
Status	Standard

Practical examples

These declarations demonstrate valid ways to set --*. The initial and inherit global keywords remain available even when a property-specific value is preferable.

--* live example

CSS

.reset-example {
  --toolio-example: initial;
}

.inherit-example {
  --toolio-example: inherit;
}

@supports (--toolio-example: initial) {
  .supported {
    --toolio-example: initial;
  }
}