The article text lives in WordPress. The interactive below is an embed
that lives on Sevalla, loaded as a custom element. Notice that when you
change the page theme above, the embed re-themes too — that's the host
page's body.cg-theme-* class cascading through Shadow DOM
via semantic tokens.
And the article continues below. Try inspecting the embed in DevTools: its styles can't leak out into this paragraph, and this paragraph's styles can't leak into the embed.