순수 CSS에서 여러 개의 고정 요소를 서로 쌓을 수 있나요?

#sticky .sticky-1,
#sticky .sticky-2
{
  position: sticky;
}
#sticky .sticky-1
{
  top: 1em;
  z-index: 1;
}
#sticky .sticky-2
{
  top: 2em;
  z-index: 1;
}

<code class="html"><div id="container">
  <article id="sticky">
    <header>
    </header>
    <main>
      <h1 class="sticky-1">Sticky heading</h1 >
      <p>here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. Some copy goes here. </p>
    </main>
    <section>
      <h2 class="sticky-2">Both headings should stick at the same time.</h2 ></code>