Don't troll. CSS cannot run arbitrary code on your device.
Via: http://stackoverflow.com/questions/718611/css-injection-what...
The interpretation and application of CSS directives is not Turing complete, but often enough to leak information from your browser.
Not true. It's definitely possible to escape the sandbox. Some examples:
https://github.com/rapid7/metasploit-framework/tree/master/m...
http://www.mozilla.org/security/announce/2013/mfsa2013-12.ht...
http://www.iss.net/security_center/reference/vuln/googlechro...
https://bugzilla.mozilla.org/show_bug.cgi?id=805121
https://www.usenix.org/legacy/event/woot08/tech/full_papers/...