This is a question that we get often at Joomlashackg and it has generated quite a bit of confusion over the years. If you do a Google search for "template.css unwritable" you can see how widespread this little bug is. Thankfully, it is normally a cosmetic issue and has no negative affect on your site.
This tutorial will provide a bit of insight into the issue and how to correct it if desired (yes, if desired).
The Problem
Whenever you edit your template.css via the Template Manager in your Joomla backend and then save, the template.css will become unwritable.
The Explanation
Although it is an issue, it a very insignificant issue as far as your site is concerned. You can still edit your template via the template manager because the template manager is designed to operate regardless of whether or not the files are writable. The notification is just there to warn you that you have left your template files writable in general.
Why have you left your template files unwritable? There is no official documentation for this, but from what I understand it is a built in security feature that the template manager editor makes the file writable when you click on edit. Then when you save, it makes it unwritable again. If that is the case, then why are all the other files writable? I am not sure, and again, there is no official documentation on this.
The Solution
Well the easiest solution is just to forget about it, because it will not affect you.
If you really want to correct it, then you can follow our two other tutorials:
- How to Change Joomla Folder and File Permissions
- Admin Tools - the Quick and Easy Way to Change Folder and File Permissions
A good point to note is that if you do correct the permissions using the Template Manager Editor again you will have the same issue, so this is only a temporary fix. However, if you use your Host's File Manager or an FTP client to edit the files, there will be no issues with permissions.
***If you have made changes to the template.css (such as logo change, etc) and the changes are not appearing on the frontend, this is not due to the template being unwritable, but just make sure to clear your browser's cache and also your site's cache.