`lit-plugin.cssTemplateTags` not working as expected

[mgenware]

For some reason, I have to use lit's html and css template literals under a namespace (re-exported by another module), lets say name.html and name.css. After setting lit-plugin.htmlTemplateTags and lit-plugin.cssTemplateTags in vscode settings, name.html works great. But for name.css, I think the underlying tokens are correctly parsed as shown below, but auto-completion and syntax highlighting are not working.