CSS function var()

Inserts the value of a custom property

Syntax

/* Simple usage */
var(--custom-prop);

/* With fallback */
var(--custom-prop,);  /* empty value as fallback */
var(--custom-prop, initial); /* initial value of the property as fallback */
var(--custom-prop, #FF0000);
var(--my-background, linear-gradient(transparent, aqua), pink);
var(--custom-prop, var(--default-value));
var(--custom-prop, var(--default-value, red));