<!DOCTYPE html>
<html>
  <head>
    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
    <title>Test unknown env() names will override previous values</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
  </head>
  <body style="background-color: green; background-color: env(unknown);">
    <script>
    test(() => {
      const style = window.getComputedStyle(document.body);
      assert_equals(style.getPropertyValue("background-color"), "rgba(0, 0, 0, 0)");
    });
    </script>
  </body>
</html>
