Ability to the style (color, radius) of Select Dropdown

[pdwonline]

I have tried all options to style the select dropdown list, for example change the background color or border-radius.
It was only possible to apply some style to the base element and also the select item in the dropdow, but not the dropdown itself.

this is what I currently use:
``

• {
  border-radius: 10px !important;
  }
  .bubble-dropdown-arrow
  {
  border-radius: 50% !important;
  }
  ``
  But as you can see, the border radius of the dropdown itself remains the same: