.breakpoint-icon {
    -fx-background-color: transparent;
    -fx-shape: "M 0 0 L 10 5 L 0 10 Z"; /* Dreieck-Symbol */
    -fx-background-insets: 0;
    -fx-padding: 0;
    -fx-background-radius: 0;
    -fx-shape-padding: 0;
    -fx-scale-shape: false;
    -fx-cursor: hand;
}