media controls: add shadow

.config/quickshell/modules/mediaControls/PlayerControl.qml

@@ -115,11 +115,25 @@ Item { // Player instance
         property color colOnSecondaryContainer: ColorUtils.mix(Appearance.m3colors.m3onSecondaryContainer, artDominantColor, 0.2)
 
     }
+    Rectangle { // Background wrapper with shadow
+        id: backgroundShadowLayer
+        anchors.fill: parent
+        anchors.margins: Appearance.sizes.elevationMargin
+        radius: root.popupRounding
+
+        layer.enabled: true
+        layer.effect: MultiEffect {
+            source: backgroundShadowLayer
+            anchors.fill: backgroundShadowLayer
+            shadowEnabled: true
+            shadowColor: Appearance.colors.colShadow
+            shadowVerticalOffset: 1
+            shadowBlur: 0.5
+        }
 
         Rectangle { // Background
             id: background
             anchors.fill: parent
-        anchors.margins: Appearance.sizes.elevationMargin
             color: blendedColors.colLayer0
             radius: root.popupRounding
 
@@ -290,3 +304,4 @@ Item { // Player instance
             }
         }
     }
+}