getComputedStyle(select1,'::picker(select)').appearance,'none');
  style.innerHTML = '#test1::picker(select) {appearance: base-select}';
  assert_equals(getComputedStyle(select1,'::picker(select)').appearance,'base-select');
  await test_driver.bless('showPicker');
  select1.showPicker();
  assert_true(select1.matches(':open'));
  style.remove();
  assert_equals(getComputedStyle(select1,'::picker(select)').appearance,'none');
  await new Promise(requestAnimationFrame);
  await new Promise(requestAnimationFr