FXWindowFramer
A JavaFX library to repaint your Applications window frame.
...), or, as a starting point, to investigate more advanced alternatives...
To keep things simple and the prototype easy to understand, FXWindowFramer only touches the application window frame (borders and nameplate), and only supports, as such, desktop applications that do not need resizing.
The goal is : Keep the painting intact, but change that frame, keeping it as simple and close to usual JavaFX initialization as possible!