This tool lets you install solid color light weight theme (also called personas, or just theme).
Unlike other themes, this theme is not using images. Just plain colors. You can choose any colors you like.
To make auto-preview in Firefox work, you must do the following:
If you don't want to allow this site, you can still preview the colors from preview box.
Win XP users: to enable custom colors in title bar, you can install Enable Personas on Title Bar user style.