<!DOCTYPE html> <html> <head> <link rel="help" href="https://drafts.csswg.org/css-env-1/"> <title>Test that CSS env vars work with @support</title> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <style> @supports (background-color: env(test)) { body { background-color: rgb(0, 128, 0); } } </style> </head> <body> <script> test(() => { const style = window.getComputedStyle(document.body); assert_equals(style.getPropertyValue("background-color"), "rgb(0, 128, 0)"); }); </script> </body> </html>