<iframe> テスト記事。
YouTube
<iframe width="560" height="315" src="https://www.youtube.com/embed/Rk1MYMPDx3s" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>↓
