use dark theme by default

Author: tibbi

app/src/main/res/values/colors.xml

@@ -1,4 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-
+    <!-- Default colors -->
+    <color name="default_text_color">@color/theme_dark_text_color</color>
+    <color name="default_background_color">@color/theme_dark_background_color</color>
 </resources>