Use DayNight theme from material-components

mobile/src/main/res/values-night/bools.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <bool name="is_day">false</bool>
+</resources>

mobile/src/main/res/values-night/colors.xml

@@ -3,4 +3,6 @@
     <color name="colorPrimary">#2e7d32</color>
     <color name="colorPrimaryDark">#005005</color>
     <color name="colorSecondary">#AEEA00</color>
+    <!-- This actually takes precedence over v27: https://developer.android.com/guide/topics/resources/providing-resources.html#BestMatch -->
+    <color name="navigationBarColor">@android:color/black</color>
 </resources>

mobile/src/main/res/values-night/styles.xml

@@ -1,4 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<resources>
-    <style name="Theme.MaterialComponents.DayNight.NoActionBar" parent="Theme.MaterialComponents.NoActionBar"/>
-</resources>

mobile/src/main/res/values/bools.xml

@@ -2,4 +2,5 @@
 <resources>
     <bool name="api_ge_26">false</bool>
     <bool name="api_lt_25">true</bool>
+    <bool name="is_day">true</bool>
 </resources>

mobile/src/main/res/values/styles.xml

@@ -1,11 +1,8 @@
 <resources xmlns:tools="http://schemas.android.com/tools">
 
-    <style name="Theme.MaterialComponents.DayNight.NoActionBar" parent="Theme.MaterialComponents.Light.NoActionBar">
-        <item name="android:navigationBarColor">@color/navigationBarColor</item>
-        <item name="android:windowLightNavigationBar" tools:ignore="NewApi">true</item>
-    </style>
-
     <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar">
+        <item name="android:navigationBarColor">@color/navigationBarColor</item>
+        <item name="android:windowLightNavigationBar" tools:ignore="NewApi">@bool/is_day</item>
         <item name="colorPrimary">@color/colorPrimary</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
         <item name="colorSecondary">@color/colorSecondary</item>