.SEESTYLE File Extension
What is a SEESTYLE file?
Style sheet file used by Coda 1 Web development software; saves settings for how the text editor window appears and includes colors for the background and source code text; replaced by the newer .SSS format in Coda 2.
To install SEESTYLE files in Coda, place them in the ~/Library/Application Support/Coda/Styles/ directory. You can then change the style sheet in the Coda Preference window in the Colors tab.