bar groups: gradient background connecting to top border

modules/BarGroup.qml

@@ -36,6 +36,16 @@ Item {
         shadowHorizontalOffset: 0
     }
 
+    // Background gradient — accent color fading down, connects to bar's top gradient
+    Rectangle {
+        anchors.fill: parent
+        radius: M.Theme.radius
+        gradient: Gradient {
+            GradientStop { position: 0; color: Qt.rgba(root.borderColor.r, root.borderColor.g, root.borderColor.b, 0.15) }
+            GradientStop { position: 1; color: "transparent" }
+        }
+    }
+
     // Visible border (on top of the glow)
     Rectangle {
         anchors.fill: parent