Before and after applying this CSS
* {
-fx-primary-color: #007acc;
-fx-secondary-color: #4B6EAF;
-fx-focus-color: -fx-secondary-color;
}
.spinner .increment-arrow-button,
.spinner .decrement-arrow-button {
-fx-background-color: -fx-primary-color;
-fx-background-radius: 0;
}
.spinner .increment-arrow-button:hover,
.spinner .decrement-arrow-button:hover {
-fx-background-color: -fx-secondary-color;
}
.spinner .increment-arrow-button:hover:pressed,
.spinner .decrement-arrow-button:hover:pressed,
.spinner .increment-arrow-button:pressed,
.spinner .decrement-arrow-button:pressed {
-fx-background-color: -fx-secondary-color;
}
.spinner .increment-arrow-button .increment-arrow,
.spinner .decrement-arrow-button .decrement-arrow {
-fx-background-color: white;
}