[whpalmer4]

Go to the Styles pane of the preferences. There's a little gear menu down at the bottom, and one of the choices is to save the current settings as a theme. Do so, saving a copy to the desktop or other convenient location. Then select that file in the Finder and use the File->Create Archive of <filename> command to turn it into a .zip file. Start a reply in the forum, and after writing your text, click the "Manage Attachments" button you'll find in the "Additional Options" section below where you compose the text. Select the .zip file and upload, then post your message. Anyone who wants to try out your theme can download it from that posting and use it.