Can anyone explain how exactly User CSS works on PRS+? I've tried looking at the PRS+ source code, but must admit that I don't see how it works. The code to select which User CSS is obvious, but I don't see how that User CSS is used by the reader.
Is the core code of the reader itself modified, or is there some magic done externally to allow the User CSS code to be loaded?
The reason I'm asking is that I'd like to try to do something like User CSS on the PRS-T1. There's no simple way (yet!) to load CSS there to (for example) let you override fonts in a single place. Some discussion about this is on this thread