I will try to set it up on new blank project tomorrow morning and post back.
Thank you guys for your support.
Wow. And it's not even tomorrow!
I guess you had things in there that were overriding your style classes configurations ?
I have no idea where it came from. I haven't set up any custom css themes. Deleting it, solved my issue!
The advanced style sheet is not linked to the themes, it's a special place where you can add custom css on top of style classes and themes.
If someone put things in there, they might have been hiding your style classes.
Deletion of that resource should tell you it had something which was being used. You're going to want to get used to examining the browser's Developer Tools to determine what style settings are being applied and from where.