<!DOCTYPE html>
<!--
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     http://creativecommons.org/publicdomain/zero/1.0/
--><html><head><title>CSS Test: Test declaring a variable that consists of a variable reference whose fallback is white space.</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>
p {
  color: red;
  --a: orange;
  --b: green;
  --a: var(--b, );
  color: var(--a);
}
</style>
</head><body><p>This text must be green.</p>
</body></html>