Implement dark theme support

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

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
 
-    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
+    <style name="AppTheme" parent="Theme.AppCompat.DayNight.DarkActionBar">
         <item name="colorPrimary">@color/primary</item>
         <item name="colorPrimaryDark">@color/primary_dark</item>
         <item name="colorAccent">@color/accent</item>