<select className="option-select">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
Here is how the basic select is defined. How to target the dropdown list UI? For example, changing the default background of the dropdown.
EDIT:
I find that it does work in Chrome if I target the <option> element. But on firefox, it does not work.
<select>because its rendering is very much driven by the host OS. Your best bet is probably to use (or create) a custom component which mimics the behavior of a<select>using other HTML elements. The framework you're using (React) likely has many available 3rd party components for this.