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CSS Variables


CSS Custom Properties (Variables)

The var() function can be used to insert the value of a custom property.


Browser Support

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

Function
var() 49.0 15.0 31.0 9.1 36.0

The var() Function

Variables in CSS should be declared within a CSS selector that defines its scope. For a global scope you can use either the :root or the body selector.

The variable name must begin with two dashes (--) and is case sensitive!

The syntax of the var() function is as follows:

var(custom-name, value)
Value Description
custom-name Required. The custom property's name (must start with two dashes)
value Optional. The fallback value (used if the custom property is invalid)

The following example first defines a global custom property named "--main-bg-color", then it uses the var() function to insert the value of the custom property later in the style sheet:

Example

:root {
  --main-bg-color: coral;
}

#div1 {
  background-color: var(--main-bg-color);
}

#div2 {
  background-color: var(--main-bg-color);
}
Try it Yourself »

The following example uses the var() function to insert several custom property values:

Example

:root {
  --main-bg-color: coral;
  --main-txt-color: blue;
  --main-padding: 15px;
}

#div1 {
  background-color: var(--main-bg-color);
  color: var(--main-txt-color);
  padding: var(--main-padding);
}

#div2 {
  background-color: var(--main-bg-color);
  color: var(--main-txt-color);
  padding: var(--main-padding);
}
Try it Yourself »

CSS var() Function

Property Description
var() Inserts the value of a custom property