I want to modify some look and feel of CS-CART's backend, but I don't know how start yet. I check the generated standaloneXXX.css, and it says:
The complete list of files it's generated from: design/backend/css/lib/ui/jqueryui.css design/backend/css/styles.less design/backend/css/glyphs.css design/backend/css/addons/help_tutorial/styles.less design/backend/css/addons/seo/styles.less design/backend/css/addons/call_requests/styles.less design/backend/css/addons/discussion/styles.less design/backend/css/addons/hybrid_auth/styles.css design/backend/css/addons/twigmo/styles.css
but I notice that there are some file like 960.gs and bootstrap in design\backend\css\lib
what is those 960 and bootstrap file used for?
You can check this or you can start modifying design/backend/css/styles.less