is there any option to change the color of the three bars of the hamburger-meue icon from black to white?
Yes, there is.
.jfx-hamburger StackPane {
-fx-background-color: white;
}
I want to change the color of the three bars, not the background. sorry if this was not clear.
But that's how you can change these bars.

.jfx-hamburger {
-fx-background-color: lightgrey;
}
.jfx-hamburger StackPane {
-fx-background-color: green;
}
@skmedix Sorry, I just can't read, you are totally right.
Any way to do it from Gluon SceneBuilder?
Most helpful comment
But that's how you can change these bars.
Example:
Code: