World Wide Web Consortium on Nostr: The CSS Working Group has published CSS Containment Module Level 1 as an updated W3C ...

The CSS Working Group has published CSS Containment Module Level 1 as an updated W3C Recommendation, incorporating the changes since the 2022 Recommendation. This CSS module describes the contain property, which indicates that the element’s subtree is independent of the rest of the page. This enables heavy optimizations by user agents when used well.
https://www.w3.org/news/2024/updated-w3c-recommendation-css-containment-module-level-1/