Colours
:color: takes any of sphinx-design's eleven semantic colours — the same
eleven a .. dropdown:: paints its summary bar with. Each becomes one CSS
class this site's stylesheet defines, so a colour nobody styled would render
as an unpainted button rather than as an error; that is why the value is
checked while parsing.
Filled
Outlined
:outline: draws the same colour as a border and text on no fill. It needs
a :color: to outline — written alone it produces no class at all, which is
why this build reports that pair rather than leaving it silently invisible
(see diagnostics).