How to add margins to Overlay？

[misumisu]

 Popup {
     id: popup
     width: 400
     height: 400
     dim: true
     visible: true

     Overlay.modeless: Rectangle {
         color: "#aacfdbe7"
         anchors.margins: 4 // here, I want to add margins
     }
 }

Using QT5.15.2。since I have margin for my entire window layout, I want to add margins for that Overlay as well