updated style

src/main/java/ch/zhaw/gartenverwaltung/SettingsController.java

@@ -12,6 +12,7 @@ import javafx.scene.image.ImageView;
 
 import java.io.IOException;
 import java.net.URL;
+import java.util.Objects;
 import java.util.ResourceBundle;
 
 /**
@@ -91,6 +92,10 @@ public class SettingsController implements Initializable {
 
         DialogPane dialogPane = dialog.getDialogPane();
 
+        dialogPane.getStylesheets().add(
+                Objects.requireNonNull(getClass().getResource("bootstrap/dialogStyle.css")).toExternalForm());
+        dialogPane.getStyleClass().add("myDialog");
+
         ButtonType save = new ButtonType("Save", ButtonBar.ButtonData.OK_DONE);
         dialogPane.getButtonTypes().addAll(save, ButtonType.CANCEL);