Revert everything back. Mission failed.

Wino.Mail/Views/Abstract/MailRenderingPageAbstract.cs

@@ -0,0 +1,26 @@
+using Windows.UI.Xaml;
+using Wino.Mail.ViewModels;
+
+namespace Wino.Views.Abstract
+{
+    public abstract class MailRenderingPageAbstract : BasePage<MailRenderingPageViewModel>
+    {
+        public bool IsDarkEditor
+        {
+            get { return (bool)GetValue(IsDarkEditorProperty); }
+            set { SetValue(IsDarkEditorProperty, value); }
+        }
+
+        public static readonly DependencyProperty IsDarkEditorProperty = DependencyProperty.Register(nameof(IsDarkEditor), typeof(bool), typeof(MailRenderingPageAbstract), new PropertyMetadata(false, OnIsComposerDarkModeChanged));
+
+        private static void OnIsComposerDarkModeChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
+        {
+            if (obj is MailRenderingPageAbstract page)
+            {
+                page.OnEditorThemeChanged();
+            }
+        }
+
+        public virtual void OnEditorThemeChanged() { }
+    }
+}