Hi again @lausianne,
Ah, I see! I apologize for the original confusion about what you needed to know.
Yes! It is true that in the styling area now you can select from a fixed selection of font sizes and fonts only.
Our goal here at MailPoet is to help you not only achieve high levels of deliverability to your subscriber list, but to ensure your subscribers remain engaged and active by making sure your emails are readable on as many different platforms and readers as possible.
For this reason, we limit the selections here to try to ensure that your mail design falls is fairly standardized, meaning it will work well with different screen sizes and readers.
If you require very special fonts for decorative reasons, the best solution would be to use images for your header areas with the exact text design you require – although please note that a high number of images in a newsletter email can also be a hinderance to delivery and opens.
That all said, if you have a need to **bold** your headings, you can do that individually on each. Once you have added the text / heading block to your newsletter, you can select the text and use the Bold button (B) in the popup menu above the block. This would have to be done on a per-heading basis as it cannot be set at the overall style level.