Default method used to render the final embedded css for the
        rendered webpage.

        Override this method in a sub-classed controller to change the output.

def render_embed_css(self, css_embed: Iterable[bytes]) -> bytes:
        """Default method used to render the final embedded css for the
        rendered webpage.

        Override this method in a sub-classed controller to change the output.
        """
        return b'<style type="text/css">\n' + b"\n".join(css_embed) + b"\n</style>"