@property --property-name {   syntax: '<color>';   inherits: false;   initial-value: #c0ffee; }  @property --property-name {   syntax: '<color>';   inherits: true;   initial-value: #c0ffee; } 

initial-value

Experimental: This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The initial-value CSS descriptor is required when using the @property at-rule unless the syntax accepts any valid token stream. It sets the initial-value for the property.

The value chosen as the initial-value must parse correctly according to the syntax definition. Therefore, if syntax is <color> then the initial-value must be a valid color value.

Syntax

@property --property-name {   syntax: '<color>';   inherits: false;   initial-value: #c0ffee; }  @property --property-name {   syntax: '<color>';   inherits: true;   initial-value: #c0ffee; } 

Values

A string with a value which is a correct value for the chosen syntax.

Formal definition

Formal syntax

<string>

Examples

Add type checking to --my-color custom property, as a color, the initial-value being a valid color:

Using CSS @property at-rule:

@property --my-color {   syntax: '<color>';   inherits: false;   initial-value: #c0ffee; } 

Using JavaScript CSS.registerProperty:

window.CSS.registerProperty({   name: '--my-color',   syntax: '<color>',   inherits: false,   initialValue: '#c0ffee', }); 

Specifications

See also

Last modified: Aug 12, 2021, by MDN contributors