Feature Request: Cut custom fonts

[minthemiddle]

To make the output even leaner and privacy-oriented, it would be great if you could programmatically remove the custom fonts and replace it with the OS default one (-apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;).