- Depending on template – typography settings can be different. If typography settings are available you can find them under Theme Settings -> Section you need to adjust, so if you want to adjust Navigation you would go to Theme Settings -> Navigation -> Typography
- Font size is missing? Well it is not missing, Mauna used adaptive typography, it tries to be bigger where is can, and it scales down where it find it appropriate. There are few places where you can adjust font size ie. Homepgae title
- If there are some typography you cannot change it probably means we do not allow, why (?), usually what may seem like a limitation is for the comfort of the user and most likely results from a reason ie. responsiveness
If you really need to make some custom changes, I would suggest using Child Theme. Make sure you buck up before you modify.