So it seems dark mode is in all apps now you need to change it in settings of each app from light to dark
My ISO was fine, it is just the notification center app that has been acting up in the last three builds.
I know that in these previews builds does not have the Greek language i keep it in english until it come out the Greek language
as i have a switch 10 tablet i would not take the change for non official builds as i had driver issues on winmain versions
I found system-wide registry setting! Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize] "AppsUseLightTheme"=dword:00000000