I came across this question in an assessment test. I know its correct for radio and checkbox. But not sure about . If it doesn't work for then what can be done to add CSS to a selected drop-down option. I tried this, but it doesn't work as well.
<!DOCTYPE html>
<html>
<body>
<style>
select { color: red; }
option:not(:checked) { color: black; }
</style>
<select>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option value="audi">Audi</option>
</select>
</body>
</html>