Theme: follow system by default

app/src/main/java/eu/faircode/email/ActivityBase.java

@@ -93,7 +93,7 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 
         if (!this.getClass().equals(ActivityMain.class)) {
-            String theme = prefs.getString("theme", "light");
+            String theme = prefs.getString("theme", "blue_orange_system");
 
             // https://developer.android.com/guide/topics/ui/look-and-feel/darktheme#configuration_changes
             int uiMode = getResources().getConfiguration().uiMode;

app/src/main/java/eu/faircode/email/ApplicationEx.java

@@ -394,6 +394,9 @@ public class ApplicationEx extends Application implements SharedPreferences.OnSh
         else if (version < 1439) {
             if (!BuildConfig.DEBUG)
                 editor.remove("experiments");
+        } else if (version < 1461) {
+            if (!prefs.contains("theme"))
+                editor.putString("theme", "blue_orange_light");
         }
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && !BuildConfig.DEBUG)

app/src/main/java/eu/faircode/email/FragmentOptionsDisplay.java

@@ -744,7 +744,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
             }
         });
 
-        String theme = prefs.getString("theme", "light");
+        String theme = prefs.getString("theme", "blue_orange_system");
         swTextColor.setEnabled(!"black_and_white".equals(theme));
 
         swTextSize.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@@ -1085,7 +1085,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
             tvSystem = dview.findViewById(R.id.tvSystem);
 
             final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
-            String theme = prefs.getString("theme", "light");
+            String theme = prefs.getString("theme", "blue_orange_system");
 
             itten.setOnClickListener(new View.OnClickListener() {
                 @Override

app/src/main/java/eu/faircode/email/HtmlHelper.java

@@ -356,7 +356,7 @@ public class HtmlHelper {
 
     private static Document sanitize(Context context, Document parsed, boolean view, boolean show_images) {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
-        String theme = prefs.getString("theme", "light");
+        String theme = prefs.getString("theme", "blue_orange_system");
         boolean text_color = (!view || (prefs.getBoolean("text_color", true) && !"black_and_white".equals(theme)));
         boolean text_size = (!view || prefs.getBoolean("text_size", true));
         boolean text_font = (!view || prefs.getBoolean("text_font", true));

app/src/main/java/eu/faircode/email/Log.java

@@ -367,7 +367,7 @@ public class Log {
                     Boolean ignoringOptimizations = Helper.isIgnoringOptimizations(context);
                     event.addMetadata("extra", "optimizing", (ignoringOptimizations != null && !ignoringOptimizations));
 
-                    String theme = prefs.getString("theme", "light");
+                    String theme = prefs.getString("theme", "blue_orange_system");
                     event.addMetadata("extra", "theme", theme);
                     event.addMetadata("extra", "package", BuildConfig.APPLICATION_ID);
                 }