How to create transparent background in ComponentActivity by jetpack compose

Question

AttachmentPickerActivity it is an activity similar to dialog, half of the screen. how to make AttachmentPickerActivity with trasparent background or something like that?

class AttachmentActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            Surface(
                modifier = Modifier.wrapContentSize()
            ){{
                    AttachmentLayout()

                }
            }

        }
    }
}