Jetpack Compose Fullscreen Dialog

I tried to make a fullscreen dialog using Jetpack Compose using this code:

Dialog(onDismissRequest = { /*TODO*/ }) {
           NewPostDialog()
       }

It ended up looking something like this. How can I remove the margin at the side (marked red)?

UPDATE: As @Nestor Perez mentioned, since compose 1.0.0-rc01 you can set usePlatformDefaultWidthin DialogProperties to make a dialog fill the whole screenwidth:

Dialog(
    properties = DialogProperties(usePlatformDefaultWidth = false),
    onDismissRequest...
    ){
      Surface(modifier = Modifier.fillMaxSize()) {
          DialogContent()
      }
    }

Compose Dialog uses ContextThemeWrapper so you should be able to theme your dialog with a custom style.

themes.xml:

 <style name="Theme.YourApp" parent="Theme.MaterialComponents.Light.NoActionBar">
       //theme content...
        <item name="android:dialogTheme">@style/Theme.DialogFullScreen</item>
    </style>

 <style name="Theme.DialogFullScreen" parent="@style/ThemeOverlay.MaterialComponents.Dialog.Alert">
        <item name="android:windowMinWidthMajor">100%</item>
        <item name="android:windowMinWidthMinor">100%</item>
    </style>

And in code:

@Composable
fun FullScreenDialog(showDialog:Boolean, onClose:()->Unit) {
    if (showDialog) {
        Dialog(onDismissRequest =  onClose ) {
            Surface(
                modifier = Modifier.fillMaxSize(),
                shape = RoundedCornerShape(16.dp),
                color = Color.LightGray
            ) {
                Box(
                    contentAlignment = Alignment.Center
                ) {
                    Text(modifier = Modifier.align(Alignment.TopCenter),
                        text = "top")
                    Text("center")
                    Text(
                        modifier = Modifier.align(Alignment.BottomCenter),
                        text = "bottom")
                }
            }
        }
    }
}