Most of you probably already saw that problem that the classes from the typography doesn’t show up in TinyMCE styles dropdown.
There are two possible solutions in respect to that issue:
1. Go to extension -> plugins and open TinyMCE, in its parameters, there is an option to load a specific CSS file called Custom CSS Classes. Place the url to your custom CSS file there.
2. Easier solution is to make a copy of your custom CSS and rename this copy to editor.css and upload it in your template css folder.
Hope it helps.