nginx and codeigniter (telling a server to put all traffic through index.php?)

[The_Rayman]

Basically, the htaccess I use with apache says something like "if the requested file or directory does not exist, route the request through index.php"How exactly can I do this with nginx?That way, if a stylesheet is requested, it's served. But if the url isn't to a file on disk, then it should run the framework.