The DOMException interface represents an abnormal event (called an exception) that occurs as a result of calling a method or accessing a property of a web API. This is how error conditions are described in web APIs.| MDN Web Docs
The @property CSS at-rule is part of the CSS Houdini umbrella of APIs. It allows developers to explicitly define their CSS custom properties, allowing for property type checking and constraining, setting default values, and defining whether a custom property can inherit values or not.| MDN Web Docs
1. Introduction| drafts.css-houdini.org