Drop a button
Set the 'style' property with:
Left text field:
-fx-background-color

text field on the right:
-fx-background-color: #ffffff14, #000000cc, #090a0c, linear-gradient(from 0% 0% to 0% 100%, #4a5661ff 0%, #1f2429ff 20%, #1f242aff 100%), linear-gradient(from 0% 0% to 0% 100%, #242a2eff 0%, #23282eff 100%), radial-gradient(focus-angle 0.0deg, focus-distance 0% , center 50% 0%, radius 100%, #878e94e5 0%, #ffffff00 100%);

Have a look on the message bar: the warning icon is truncated.