alt: color of scrollbar in popup menu

HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/PopupMenu.java

@@ -38,6 +38,7 @@ public class PopupMenu extends Control {
     private final BooleanProperty alwaysShowingVBar = new SimpleBooleanProperty();
 
     public PopupMenu() {
+        getStyleClass().add("popup-menu");
     }
 
     public ObservableList<Node> getContent() {
@@ -82,7 +83,7 @@ public class PopupMenu extends Control {
                     .otherwise(ScrollPane.ScrollBarPolicy.AS_NEEDED));
 
             VBox content = new VBox();
-            content.getStyleClass().add("menu");
+            content.getStyleClass().add("content");
             Bindings.bindContent(content.getChildren(), PopupMenu.this.getContent());
             scrollPane.setContent(content);
 

HMCL/src/main/resources/assets/css/root.css

@@ -106,7 +106,11 @@
     -fx-padding: 8 16 8 16;
 }
 
-.menu {
+.popup-menu .scroll-bar .thumb {
+    -fx-fill: rgba(0, 0, 0, 0.5);
+}
+
+.popup-menu .content {
     -fx-padding: 4 0 4 0;
 }