Custom CSS can break Styleguidist's styles

Current behavior

requiring a custom CSS in the config can break Styleguidist's styles. In my case the CSS is semantic-ui and the Styleguidist styles are section headers and bodies. Would there be a way to fix this? I imagine quite some scenarios require using a custom CSS.

This is getting into feature request territory and I'm really just guessing about stuff I know very little about, but since Styleguidist is already using JSS, maybe applying a CSS reset specifically to Styleguidist components would work? Or putting examples in iframes?

To reproduce

https://github.com/andrewpeterprifer/example

Expected behavior

Styleguidist styles should be preserved.