I posed a similar question just now....
Font Size and Line Height issues on export
I wanted to let you know I am having issues on export with the base font size of 12px and 14px, as well as the base line-height of 21 exporting on the outside div.
This is a constant on all exports even though I change the font size to 16 or 18 and the line height to 29.
My current solution is taking my BeePro exports into Dreamweaver or brackets and deleting or using find and replace the base font sizes and line heights because if I leave them in some email clients, such as Outlook, will read those instead, therefore causing my email to read funny.
Here is a screenshot...