Detect at-rule support in CSS with @supports at-rule(@keyword)

Back in January 2022, I wrote about an exciting new CSS Working Group decision: a function to detect at-rule support using @supports at-rule(@keyword). Fast forward to today, and the CSS Conditional Rules Module Level 5 specification has solidified how this feature works and Chromium (Chrome, Edge, etc.) is about to ship it in Chromium 148!