Cannot style Choicebox Dropdown

I am trying to change the background color and hover color of the drop down menu that appears in a choice box. when I preview the attached code in SceneBuilder, the style is applied properly: the drop down has a red background and the hover over color is salmon. The other rules are applied as well.

If I compile the code and run it, the dropdown appears in default grey and the hover over in default blue.

The .context-menu and #choice-box-menu-item:hover css selector rules are not being applied in compiled code.