JavaFxSceneBuilder - Styling MenuItem

Question

I am trying to style my menu-item, but so far unsuccessful.

Hierarchy

I tried below css, but nothing. Can anyone help?

.menu-bar .menu:openvertically .arrow-button .arrow{

 -fx-background-color:red;

}

I don't understand how to access the children of MenuBar.

I could, however change the Menu, using CSS below.

.menu-bar .menu:openvertically .label{
 -fx-text-fill: orange;
 -fx-padding: 5 0 0 20;
 -fx-font-size: 18pt;

}

Thanks!