Anyone has how to define a theme in the mobile version different than the one in the desktop version?

Thanks Jamie!

So, it seems that is technical possible to define different theme, great.

Now the only missing part is how to disable the "auto-detection" and select the mobile or desktio version according to the starting url, so I can point the PWA starting page to the mobile and let the responsive desktop for browsers (even in mobiles).

Yes! It is possible to add several themes in your mobile and desktop. AN whatsapp provides a lot of themes. you can use for your whatsapp. NA WhatsApp is a modified version of the widely-used messaging app, WhatsApp. It has extra features that aren’t available in the original app. With NA WhatsApp, you have more control over your privacy. For example, you can hide your “last seen” status while still being able to reply to messages. You can also download status updates directly to your phone, eliminating the need for additional third-party apps.