<!DOCTYPE html>
<meta charset="utf-8">
<title>Shared style invalidation with removals</title>
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1707116">
<link rel="help" href="https://drafts.csswg.org/css-scoping/">
<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
<link rel="author" href="https://mozilla.org" title="Mozilla">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="host-1"></div>
<div id="host-2"></div>
<script>
const INITIALLY_COMMON_STYLE = `<style>:host { background-color: red !important }</style>`;
let helper = document.querySelector("#host-1");
let host = document.querySelector("#host-2");

test(function() {
  helper.attachShadow({ mode: "open" }).innerHTML = INITIALLY_COMMON_STYLE;
  assert_equals(getComputedStyle(helper).backgroundColor, "rgb(255, 0, 0)", "Common style should apply to helper");

  host.attachShadow({ mode: "open" }).innerHTML = INITIALLY_COMMON_STYLE;
  assert_equals(getComputedStyle(host).backgroundColor, "rgb(255, 0, 0)", "Common style should apply to host");

  host.shadowRoot.innerHTML = `<style>:host { background-color: lime; width: 100px; height: 100px; }</style>`;
  assert_equals(getComputedStyle(host).backgroundColor, "rgb(0, 255, 0)", "Common style should no longer apply to host");
});
</script>
