So you’re editing away on the server and all the sudden, your styling disappears. Disconcerting? Absolutely. But you’ve come to the right place for a solution.
One of two things could be happening with a permissions error (especially if you had everything working before). The less likely is that something was messed up with the .htaccess file. In this case, you’d need to go in and repair it. WordPress will fix the .htaccess file whenever you update your permalink structure…just a hint.
The second, and more likely problem is that your software somehow saved the file with the wrong permissions. When you upload it to the server, the permissions stayed the same. So here’s the fix:
1. Update the file’s permissions to 755. (That’s rwxr-xr-x)
(That’s the whole solution.)
The basic idea is that the file needs to be able to execute and be read by the world. The first set of 3 applies to the user (i.e. the php file), the second applies to the group (i.e. a workgroup) and the third to everyone else. In this case, the permissions are probably set so that the file cannot execute at all and perhaps not be read by either group or world. So your browser can’t send a request to the file, because the permission is denied.
So there you have it! Pure and simple file permissions!