There has been a change to the reputation color of the top-bar, I think this is part of the new themes of the Stack Exchange network.
But it makes it very hard to read on all sites, I've created an account on ru, ja, pt, and had one on es and can confirm it's happening on all sites.
Here is an image from ja
The 300+ rep is because I joined those sites.
And here is one from es
Here is an image of the classes that affect the reputation, as we can see they are
.top-bar .my-profile .-rep