<!DOCTYPE html>
<html>
<head>
<style id="ref">
:host, :host(.hidden) {
    display: none;
}
</style>
</head>
<body>
<pre id="out"></pre>
<script>
if (window.testRunner)
    testRunner.dumpAsText();

const el = document.getElementById('ref');
const out = document.getElementById('out');

const rule = el.sheet.rules[0];
out.innerText = rule.cssText;
</script>
</body>
</html>

