fix wrong navbar color in ViewMediaActivity & ViewVideoActivity on Android 8.1+

app/src/main/AndroidManifest.xml

@@ -68,12 +68,14 @@
         </activity>
         <activity
             android:name=".ViewVideoActivity"
+            android:theme="@style/AppThemeBase"
             android:configChanges="orientation|keyboardHidden|screenSize" />
         <activity
             android:name=".ViewThreadActivity"
             android:configChanges="orientation|screenSize" />
         <activity android:name=".ViewTagActivity" />
-        <activity android:name=".ViewMediaActivity" />
+        <activity android:name=".ViewMediaActivity"
+            android:theme="@style/AppThemeBase" />
         <activity android:name=".AccountActivity" />
         <activity android:name=".EditProfileActivity" />
         <activity android:name=".PreferencesActivity" />