An Amazing, Free & Web-Based CSS Editor: bluePen Editor
When we need to update the styles of websites that are already online, we either perform the change locally (if we have the source with us) or FTP-edit it.
bluePen Editor is a PHP-powered CSS editor that can be installed to any static or dynamic website and makes live CSS editing possible.
Once triggered (with a bookmarklet), it opens the editor widget and makes all HTML elements hoverable so that blupePen can locate the CSS rules of them (like Chrome Dev Tools).
It has features like color-picker, file manager, ruler, color comparison and more.
The editor keeps track of the changes made and auto-backups them in case you prefer to revert the styles.