<!DOCTYPE html>
<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
<link rel="help" href="https://drafts.csswg.org/cssom/#the-csspagerule-interface">
<title>Add / remove margin rules inside an @page rule</title>
<style id="sheet">
  @page { }
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
  let sheet = document.getElementById("sheet").sheet;
  let pageRule = sheet.rules[0];

  test(() => {
    assert_