How can I style a JavaFX SplitMenuButton in CSS

Question

I try to style a SplitMenuButton in JavaFX. I've got a menuButton and a SplitMenuButton in my fxml-file.

My CSS-File looks like this:

.menu-button {
    -fx-background-color: red;
    }

.split-menu-button .label {
    -fx-background-color: green;
    }

.split-menu-button .arrow {
    -fx-background-color: yellow;
    }

But I can't figure out how to style the area around the arrow for the SplitMenuButton. I tried several ways, but nothing worked

.split-menu-button .menu-button {
    -fx-background-color: blue;
    }

.split-menu-button .menu-button .label {
    -fx-background-color: blue;
    }

.split-menu-button .menu{
    -fx-background-color: blue;
    }

.split-menu-button .menu-item {
    -fx-background-color: blue;
    }

.split-menu-button .button {
    -fx-background-color: blue;
    }

.split-menu-button .menu-bar {
    -fx-background-color: blue;
    }

Answer 1

There are two useful techniques for figuring out the style classes for individual parts of complex components like this:

1. Extract the default style sheet, modena.css, from the jfxrt.jar file and see how the default styles are defined (you can also find modena.css online)
2. Use ScenicView to inspect your application when it's running

In this case I used ScenicView; the css you need is

.split-menu-button .arrow-button {
    -fx-background-color: yellow ;
}