The CSS Working Group has published an updated Working Draft of CSS Cascading and Inheritance Level 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 changes have been made since the previous Working Draft:
- Unlayered styles now have the lowest priority in normal origins, rather than the highest. This is designed to help with author expectations and progressive enhancement, so that more explicit layers have a higher weight than the default, while unlayered
!importantstyles remain at the top of the priority order.
Please send feedback by either filing an issue in GitHub (preferable) or sending mail to the (archived) public mailing list www-style@w3.org with the spec code ([css-cascade-5]) and your comment topic in the subject line. (Alternatively, you can email one of the editors and ask them to forward your comment.)