CSS --* Custom Property

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:root {
  --first-color: red;
  --bg-color: green;
  --width: 150px;

p {
  color: var(--first-color);
  background: var(--bg-color);
  width: var(--width);


The --* custom property names that are prefixed with --, like --exampleName, represent custom properties that contain a value that can be used in other declarations using the var() function.

Note: Custom property names are case sensitive: --my-color will be treated as a separate custom property to --My-color.

Default value:(default value of the property)
JavaScript syntax:
object.style.setProperty("--exampleName", "css property value(s) |initial|inherit|revert|revert-layer|unset");

Standard Syntax

:root {
  --*: css property value(s) |initial|inherit|revert|revert-layer|unset;

Browser Support

The numbers in the table specify the first browser version that fully supports the property.


Property Values

The following table describes the values of this property.

Value Description
css property value(s) It represents the entirety of what a valid declaration can have as its value.
initial Sets this property to its default value.
inherit If specified, the associated element takes the computed value of its parent element animation-delay property.
revert Reverts the cascaded value of the property from its current value to the value the property
revert-layer Rollback styles to the ones specified in previous cascade layers.
unset Resets a property to its inherited value if the property naturally inherits from its parent, and to its initial value if not.

Default CSS Property Values

selectors {
  --*: (default value of the property);
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