Webpages don't apply background transparency from OBS

[GrandyB]

When adding a normal webpage to OBS, it injects some CSS in to remove the background. This removes the dark navy background from OBSNinja for instance, so that when the feed isn't playing, it's transparent and not visible. This is not the case for the html type in SheetsIO.

In our case, OBS is applying that html to the container of the document and not to the content of what is currently an iframe. Looks like iframes can't have their inner content altered due to chrome's policies; perhaps OBS itself might be able to - unsure.

Either way, would be good to address this difference if possible.