overlay: refractor widget background

dots/.config/quickshell/ii/modules/ii/overlay/OverlayBackground.qml

@@ -0,0 +1,8 @@
+import QtQuick
+import qs.modules.common
+
+Rectangle {
+    id: contentItem
+    anchors.fill: parent
+    color: Appearance.m3colors.m3surfaceContainer
+}

dots/.config/quickshell/ii/modules/ii/overlay/fpsLimiter/FpsLimiterContent.qml

@@ -6,16 +6,15 @@ import Quickshell
 import Quickshell.Io
 import qs.modules.common
 import qs.modules.common.widgets
+import qs.modules.ii.overlay
 
-Rectangle {
+OverlayBackground {
     id: root
 
     enum State { Normal, Success, Error }
 
-    anchors.fill: parent
     property real padding: 16
     property var currentState: FpsLimiterContent.State.Normal
-    color: Appearance.m3colors.m3surfaceContainer
     implicitWidth: content.implicitWidth + (padding * 2)
     implicitHeight: content.implicitHeight + (padding * 2)
 

dots/.config/quickshell/ii/modules/ii/overlay/recorder/Recorder.qml

@@ -12,11 +12,9 @@ StyledOverlayWidget {
     minimumWidth: 310
     minimumHeight: 130
 
-    contentItem: Rectangle {
+    contentItem: OverlayBackground {
         id: contentItem
-        anchors.fill: parent
         radius: root.contentRadius
-        color: Appearance.m3colors.m3surfaceContainer
         property real padding: 8
         ColumnLayout {
             id: contentColumn

dots/.config/quickshell/ii/modules/ii/overlay/resources/Resources.qml

@@ -37,10 +37,8 @@ StyledOverlayWidget {
         },
     ]
 
-    contentItem: Rectangle {
+    contentItem: OverlayBackground {
         id: contentItem
-        anchors.fill: parent
-        color: Appearance.m3colors.m3surfaceContainer
         radius: root.contentRadius
         property real padding: 4
         ColumnLayout {

dots/.config/quickshell/ii/modules/ii/overlay/volumeMixer/VolumeMixer.qml

@@ -13,9 +13,7 @@ StyledOverlayWidget {
     minimumWidth: 300
     minimumHeight: 380
 
-    contentItem: Rectangle {
+    contentItem: OverlayBackground {
-        anchors.fill: parent
-        color: Appearance.m3colors.m3surfaceContainer
         radius: root.contentRadius
         property real padding: 6