The skin is one thing. My big challenge is still to come. Currently, you have to manually copy and replace the color scheme files. I'd like to develop a plugin that does this from within the Opnsense GUI. It's actually quite simple: you'd just have to display the subdirectories in a specific folder named after the theme name in a listbox, and then copy the default-scheme.css contained in each of these subfolders into the theme's build/css/ folder. The whole thing could be enhanced with a screenshot of the skin. The crowning glory, of course, would be a color picker. Surely simple for a professional programmer, but for me, who's never worked with PHP, etc., it's a mystery. But let's see what I can come up with. Maybe a pro will enjoy the idea and offer a little support for a beginner. ;-)