drag over highlight

src/main/java/com/sparrowwallet/sparrow/AppController.java

@@ -32,6 +32,7 @@ import java.util.ResourceBundle;
 
 public class AppController implements Initializable {
     private static final String TRANSACTION_TAB_TYPE = "transaction";
+    public static final String DRAG_OVER_CLASS = "drag-over";
 
     @FXML
     private CheckMenuItem showTxHex;
@@ -70,6 +71,14 @@ public class AppController implements Initializable {
             event.consume();
         });
 
+        rootStack.setOnDragEntered(event -> {
+            rootStack.getStyleClass().add(DRAG_OVER_CLASS);
+        });
+
+        rootStack.setOnDragExited(event -> {
+            rootStack.getStyleClass().removeAll(DRAG_OVER_CLASS);
+        });
+
         tabs.getSelectionModel().selectedItemProperty().addListener((observable, old_val, selectedTab) -> {
             if(selectedTab != null) {
                 String tabType = (String)selectedTab.getUserData();

src/main/resources/com/sparrowwallet/sparrow/app.css

@@ -1,5 +1,5 @@
 .background-box {
-    -fx-stroke: #696c77;
+    -fx-stroke: #a0a1a7;
     -fx-stroke-width: 1px;
     -fx-stroke-dash-array: 5 5;
     -fx-arc-height: 50;
@@ -7,7 +7,15 @@
     -fx-fill: transparent;
 }
 
+.drag-over > .background-box {
+    -fx-stroke: #383a42;
+}
+
 .background-text {
-    -fx-fill: #696c77;
+    -fx-fill: #a0a1a7;
     -fx-font-size: 20;
 }
+
+.drag-over > .background-text {
+    -fx-fill: #383a42;
+}