Guaranteed-invalid value

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In CSS the guaranteed-invalid value is {{CSSXref("initial")}} .

When a custom property’s value is the guaranteed-invalid value, the {{CSSXref("var")}}  function cannot use it for substitution. Attempting to do so makes the declaration invalid at computed-value time, unless a valid fallback is specified.

See also

• CSS {{CSSXref("initial")}} 
• CSS {{CSSXref("var")}} 
• CSS Custom Properties for Cascading Variables Module Level 1 Specification