Used contain values different from none on the root or body elements will disable propagation of CSS properties from body as per specification[1]. [1] https://drafts.csswg.org/css-contain-1/#c3
Specification
Final published standard: Recommendation, Living Standard, Candidate Recommendation, or similar final form
Status in Chromium
Enabled by default
(tracking bug)
Consensus & Standardization
After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.
Owner
Last updated on 2022-01-04
Comments
The relevant part of the spec is a correction of a W3C Recommendation.