Added dark mode 🦇

src/Artemis.UI/Events/WindowsThemeEventArgs.cs

@@ -0,0 +1,15 @@
+using System;
+using Artemis.UI.Utilities;
+
+namespace Artemis.UI.Events
+{
+    public class WindowsThemeEventArgs : EventArgs
+    {
+        public WindowsThemeEventArgs(ThemeWatcher.WindowsTheme theme)
+        {
+            Theme = theme;
+        }
+
+        public ThemeWatcher.WindowsTheme Theme { get; set; }
+    }
+}