In your css the color of the text is set in this style:
menu.css line 52
ul#cssmw_home > li > span > a
It is the color property that is responsible for the color.
The background images for the navigation menu are creating this effect on the page you linked to. If you remove the solid black background from this style:
common.css line 140
#outerWrapper #navWrapper {
The other part is controlled by the background image on the nav itself:
common.css line 149
#outerWrapper #navWrapper #topNavigation {
The menu for the PowerStore can be edited with CSS Menu Writer so long as it has not been altered manually. You can get this back to normal with the original main template, this is the file that contains the menu. You can replace the menu folder and the main template if you need to get back to the original.
