The files that we currently export have CSS variables that once imported, can be used anywhere in your app! With this set up, instead of needing to reference arbitrary hex colors throughout your CSS, you now have a code-based source of truth for your colors and design tokens.
For existing apps, there is definitely a bit of a migration process, appreciate that callout! The good news is that its a migration that can happen over time, as using Mirrorful isn't dependent on your whole codebase being consistent on day 1. We're also looking to leverage AI to do auto-migrations!
We currently don't have a direct integration with Bootstrap, but we definitely work with Bootstrap! I just created a Github Issue for us to create an example to show how you can use Mirrorful with Bootstrap: https://github.com/Mirrorful/mirrorful/issues/260