This has nothing to do with your text editor. When I read that line of discussion, I started to think this must be a troll, rather than an actual problem...
but I don't use AJAX
Do you mean that you have disabled AJAX page loading, or do you mean something else? If so, why do you disable AJAX? This is going to create a poor UI experience for the user, with ugly flashing page changes.
If you disable AJAX page loading, this can't possibly work, because then the document is completely reloaded on each page change, and so the site base directory changes when you go down into a directory.
../ won't work then, in most browsers, because browsers disallow navigating up from the base. Maybe you never navigate back up once a language is chosen, though?
Links from within the it directory to the same directory should have NO prefix. e.g.
somepage.html, not
it/somepage.html. The latter, of course, will try to navigate to
it/it/somepage.html.
If you use Ajax page loading, then it will work if you use proper relative URLs, until/unless the user presses the browser refresh inside a subdirectory, and then it will stop working because that will reset the base directory.
Do I read you correctly that you expect the user to download a .zip file and install it locally? Who is going to bother with that? This won't work unless the mobile user has an alternative browser that implements it's own local filesystem. You are limiting yourself to a very small slice of users.
Why not create a proper webapp? You simply have to create a manifest file. You don't need to use relative URLs then, because the mobile OS takes care of that when it wraps the webapp with a native app. As well, then it runs in "full screen" mode, and there is no browser chrome, and so no possibility that the user will hit browser refresh.