Accessing the CSS file

My developer asked:

"How can I access the CSS style file for all the pages?"

"I need the CSS files simple as that so I can edit them through notepad++"

NOTE: The site is made in PHP, MySQL, SFTP, and Dolphin by Boonex.

Your developer should be a member of the forums where she/he can ask directly.  The code is available for download so your developer should have a copy of it sitting on their local computer.