The CSSUnparsedValue interface of the CSS Typed Object Model API represents property values that reference custom properties. It consists of a list of string fragments and variable references.
Custom properties are represented by CSSUnparsedValue and var() references are represented using CSSVariableReferenceValue.
Returns an array of a given object's own enumerable property [key, value] pairs in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).