Why are there two css files

[xeruf]

It is confusing to have both files there and not knowing which one to update when submitting a PR. What about a script that creates one out of the other and a simple note which one to edit?

[xeruf]

And it's even worse requiring that you have to apply the exact same changes to both files when you submit a PR, that scares away contributors...

[snowe2010]

There are two css files because the two must both be maintained, one for userstyles.org and one for user css. Many other userstyles do this. If you would like to submit a contribution that does what you say, that would be very welcome!