First Public Working Draft: CSS Environment Variables Module Level 1

The CSS Working Group has published a First Public Working Draft of CSS Environment Variables Module Level 1. This specification defines the concept of environment variables and the env() function, which work similarly to custom properties and the var() function, but are defined globally for a document. These can be defined either by the user agent, providing values that can be used on the page based on information the UA has special access to, or provided by the author for "global" variables that are guaranteed to be the same no matter where in the document they’re used.