Add dark theme logo

Author: JHWelch

README.md

@@ -51,5 +51,10 @@ If we receive enough donations we might even be able to free up some working hou
 To donate, please follow [this](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=G5D8E9MR5DTD2&source=url) link.
 
 <p style="text-align: center">
-  <a href="https://forum.magicmirror.builders/topic/728/magicmirror-is-voted-number-1-in-the-magpi-top-50"><img src="https://magicmirror.builders/img/magpi-best-watermark-custom.png" width="150" alt="MagPi Top 50"></a>
+  <a href="https://forum.magicmirror.builders/topic/728/magicmirror-is-voted-number-1-in-the-magpi-top-50">
+    <picture>
+      <source media="(prefers-color-scheme: dark)" srcset="https://magicmirror.builders/img/magpi-best-watermark.png">
+      <img src="https://magicmirror.builders/img/magpi-best-watermark-custom.png" width="150" alt="MagPi Top 50">
+    </picture>
+  </a>
 </p>