Optional ReadonlydocumentDocument to read from. Defaults to the ambient one.
Optional ReadonlymatchOnly keep rules whose selector mentions one of these strings. Defaults to the editor's own prefixes, so a host page's unrelated CSS is left out. Pass an empty array to keep everything.
Gather the CSS a page has already parsed, so an exported document can carry its own styling instead of linking back to the server it came from.
A link to
http://localhost:5173/assets/x.cssonly renders while that server is running and reachable. A file saved to disk, mailed to someone, or opened tomorrow gets nothing, which is exactly what "the style is not working" looks like.