use proper menu colors at fullscreen view

app/src/main/kotlin/com/simplemobiletools/gallery/pro/activities/ViewPagerActivity.kt

@@ -84,6 +84,10 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
 
     override fun onCreate(savedInstanceState: Bundle?) {
         useDynamicTheme = false
+        if (config.isUsingSystemTheme) {
+            setTheme(R.style.AppTheme_Material)
+        }
+
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_medium)
 

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

@@ -2,6 +2,12 @@
 
     <style name="AppTheme" parent="AppTheme.Base"/>
 
+    <style name="AppTheme.Material" parent="AppTheme">
+        <item name="actionOverflowMenuStyle">@style/TopPopupMenuYou</item>
+        <item name="actionBarPopupTheme">@style/TopPopupMenuTextYou</item>
+        <item name="actionBarStyle">@style/AppTheme.ActionBar</item>
+    </style>
+
     <style name="FullScreenTheme.Base" parent="AppTheme">
         <item name="android:windowContentOverlay">@null</item>
         <item name="android:windowTranslucentNavigation">true</item>