You should be able to edit gallery.css to change the colors. If you have Firefox, you can use the Web Developers Toolbar (extension) to see the ID and CLASS names of the various elements in the front-end layout.
Dull, yes, it was designed to be embedded in your existing website not to be used by itself.
Also as (if not more useful) is the Firefox DOM Inspector. When installing FF, choose a "Custom" installation ... it will give you the option to add the DOM Inspector. Then, just use Ctrl + Shift + I to navigate and inspect the DOM tree.
firebug (another ff extension) is great too. https://addons.mozilla.org/firefox/1843/
ctrl+shift+c (I think that's the defualt) to hover over anything anything and it highlights it in a dom tree. I dunno how I ever built websites without the Web Dev Toolbar and Firebug. ;P