<!DOCTYPE html> <html> <head> <link rel="help" href="https://drafts.csswg.org/css-env-1/"> <title>Test env() will work in custom properties</title> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <style> #parent { --var1: inherited; } #child { --my-width: env(test, 100px); width: var(--my-width); --var1: env(nonexistent); } </style> </head> <body> <div id="parent"> <div id="child"></div> </div> <script> test(() => { const style = window.getComputedStyle(child); assert_equals(style.getPropertyValue("width"), "100px"); }, 'env() is substituted into a custom property'); test(() => { const style = window.getComputedStyle(child); assert_equals(style.getPropertyValue("--var1"), ""); }, 'Substitution of unrecognized env() causes guaranteed-invalid'); </script> </body> </html>