Open developer tools/inspector and click somewhere on the page, or an element in the html (<div>, <p> or whatever). Under "rules" it will tell you from which file it is pulling the styles for the selected dom element.

I found what I needed using about:cache, extracted the file with chromecacheview, copied the text by opening it in Chrome and finally pasted the text into Stylebot as a new CSS to get my old view of the site back.

Little things please little minds.

Your second response is exactly what I was asking for.

Well, I got there in the end.