如何在Android中删除AlertDialog标题的默认填充/边距

<style name="CustomAlertDialog" parent="Theme.AppCompat.Light.Dialog.Alert">
    <item name="android:windowTitleStyle">@style/CustomDialogTitle</item>
</style>

<style name="CustomDialogTitle">
    <item name="android:padding">0dp</item>
    <item name="android:background">@android:color/transparent</item>
</style>

AlertDialog.Builder builder = new AlertDialog.Builder(context, R.style.CustomAlertDialog);
builder.setTitle("标题")
       .setMessage("消息内容")
       .setPositiveButton("确定", new DialogInterface.OnClickListener() {
           @Override
           public void onClick(DialogInterface dialog, int which) {
               // 确定按钮点击事件
           }
       })
       .setNegativeButton("取消", new DialogInterface.OnClickListener() {
           @Override
           public void onClick(DialogInterface dialog, int which) {
               // 取消按钮点击事件
           }
       })
       .show();