I've found how to enable different user select-able themes. I've installed some free colour styles / themes for you to pick from, but each requires a boatload of programming / updates to get 100%. As such, they all currently show default branding, and lots of default links that do not do anything, etc.
For the helping your eyes not hurt, they should be perfect, but I'll need to roll out updates to each theme over the coming weeks before they will be 100% functional. (Consider it a beta test for now while I work in the coming weeks)
To update which theme you use, at the very bottom of this page it says "Default Style" on the left, click that, and pick a new theme. To change back after, the link moves, and will be called the theme name. For example if you turn on the "Iodine" theme, then look at the footer area for the word "iodine" to change the theme again.