The remaining changes in appearance are generally taylored with custom themes. Simply browse the section here for the various threads and have a look at the tons of them available!
The advanced color section there is mainly for tweaking the appearance once you have a theme applied for changing borders, inactive backgrounds in windows, etc. as you look those over. You can easily reverse any changes after clicking the apply to see how that works by reappying the defaults or changing the item changed to the original.
If you go into the expanded color chart seen when dropping down the "color 1" tab you can raise or lower color intensity as well by fading from one color to another.