Lantern, a browser extension for highlighting and annotating webpages: https://chromewebstore.google.com/detail/lantern/jjoijlenmgefkaeiomoaelcljfibpcgh
This is very hard to do but it actually works ...
I guess you could annotate when pages with the built in code editors and to allow the code as a localhost style sheet that remembers the web page might work, but then there would have to be a hash function that let you know the original was updated or changed.