VTT file with embedded style sheet with ::cue not working

See the STYLE section of the VTT file shown at the bottom. If that’s embedded in the HTML file, the styling works.
Uncomment the styles in the html above to see it work.


Here's the stylesheet embedded in the VTT file:
		WEBVTT

		STYLE
		::cue(.red){ color: red; }


		1
		00:00:00.100 --> 00:00:50.000
		<c.red>This should be a red caption</c>