Feature Detecting “Undetectable” CSS Features with @supports named-feature()

In CSS you can feature detect support for things like selectors, properties + values, and at-rules using @supports. But how do you feature detect a change to an underlying implementation, or two existing properties suddenly working together? Enter @supports named-feature(), a function designed to expose these specific capabilities without relying on hacky workarounds.

https://www.bram.us/2026/08/27/feature-detecting-undetectable-css-features-with-supports-named-feature/