The obvious answer is to refresh, refresh, refresh, but I am guessing you have done this already. Then purge your history and restart and refresh and so on. But you have probably done this also.
Sometimes I find the best way is in fact to use the direct url to your CSS to check it is actually the correct one ie. http://yoursite.com/css/styles.css
If your in Firefox using Firebug to inspect elements is also a great way to see what your stylesheets are doing.
Last but not least change the file name of your css and ensure you relink. That means a fresh url not being cached by your ISP.
That is the only advice I can give ebough though it is all the base solutions to check.
Can you please send me a PM with the files you are changing and are not viewing properly through the front-end of the site? If you could include a screenshot with the changes you have just made (how the file should look) and the method you used to edit the file (via FTP or the Admin Console or the new File Manager) it would be great.
The hotpatch Alan mentioned above was targeting a different issue - templates or pages sometimes reverted to a previous version. That was a completely different issue (even though the manifestation might be similar to this one) and we have received confirmations it has been fixed.