<!DOCTYPE html>
<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
--><html><head><title>CSS Test: Test a failing custom property declaration in an @supports rule whose value contains a variable reference with fallback containing a top level "!important".</title>
<link href="mailto:cam@mcc.id.au" rel="author" title="Cameron McCormack">
<link href="http://www.w3.org/TR/css-variables-1/#syntax" rel="help">
<link href="support/color-green-ref.htm" rel="match">
<style>
body { color: red; }
@supports (--a: a) and (not (--a: var(--b,!important))) {
  p { color: green; }
}
</style>
</head><body><p>This text must be green.</p>
</body></html>