Fixed status bar color on older Android versions

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

@@ -264,7 +264,7 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
             WindowInsetsControllerCompat controller = WindowCompat.getInsetsController(window, window.getDecorView());
             controller.setAppearanceLightStatusBars(false);
             controller.setAppearanceLightNavigationBars(false);
-            window.setNavigationBarColor(ColorUtils.setAlphaComponent(colorPrimaryDark, 128));
+            window.setNavigationBarColor(Color.TRANSPARENT);
         }
 
         String requestKey = getRequestKey();