Google Chrome: <img width="612" alt="Screenshot 2020-04-02 at 08 37 55" src="https://user-images.githubusercontent.com/19679857/78208227-4e542600-74bd-11ea-8056-4a21b3f8e5f7.png"> It seems like the button element has default browser styles thus 11px font size. Where 1em = 16px
Google Chrome:

It seems like the button element has default browser styles thus 11px font size. Where 1em = 16px