When building a custom CSS pipeline via CSS: and HTML Header: metadata
keys, there's no way to preview the document with only those styles applied.
The Style picker always requires at least one registered style. A "None" option
would let users see exactly what their metadata-injected CSS produces in the
preview.
I also raise this because the HTML export option does allow exporting without
a theme attached, but that means there's no consistent stylesheet view from
preview to export.
I've also made good use of the Dingus, but it doesn't seem to show updated
previews for metadata like the CSS: tag until the file is saved and returns
to the main preview window.
This would be especially useful for workflows where the entire stylesheet is
managed externally via MMD metadata.
