[CSSWG][css-cascade-5] FPWD of CSS Cascading and Inheritance Level 5

The CSS WG has published a First Public Working Draft of CSS Cascading and Inheritance Level 5:

https://www.w3.org/TR/css-cascade-5/

This CSS module describes how to collate style rules and assign values by way of cascading and inheritance.

Level 5 adds “layers” to the cascade, along with a syntax for defining and sorting those layers. In the same way that cascade origins provide a balance of power between user and author styles, cascade layers provide a structured way to organize and balance concerns within a single origin – such as element defaults, third-party libraries, themes, components, and overrides.

The following features have been added since Level 4:

* Added cascade layers to the cascade sort criteria.
* Defined style attributes as a distinct step of the cascade sort criteria.
* Introduced the @layer rule for defining cascade layers

This is a First Public Working Draft and the features herein are subject to change. Implementers should track open issues and ongoing discussions:

https://github.com/w3c/csswg-drafts/issues?q=is%3Aopen+is%3Aissue+label%3Acss-cascade-5

Please review the draft, and send any comments to this mailing list, <www-style@w3.org>, prefixed with [css-cascade-5] (as I did on this message) or (preferably) file them in the GitHub repository at https://github.com/w3c/csswg-drafts/issues

For the CSS WG,
-Miriam