nautilus css issue

[Iss-in]

Hi, not exactly an issue, more of a question exactly
I was playing around with the theme , source files and final gtk.css,
I couldn't figure out the part of css which control the nautilus/thunar navigation button part ( back, home buttons etc.)
I dig around a lot, but couldn't find anything related to them..
can you please point out them for me...
sorry for inconvience if any