Hi -  Based upon your question and playing around with your menu, I am assuming you mean the light blue that the menu item turns when a user onclicks an item, ie it turns blue when I click Inicio.  I was able to change the blue to red by replacing the color listed below to 'red'.  

In the Default.CSS file, towards the bottom, you should find the following:

.MainMenu_MenuItemSel

{

	cursor: pointer;

	color: black;

	font-family: Tahoma, Arial, Helvetica;

	font-size: 9pt;

	font-weight: bold;

	font-style: normal;

	background-color: #C1D2EE;

} 

Thanks for you interest.

I have this code:

.MainMenu_MenuItemSel

background-image: url(imgs/fundoalphamenu.png);cursor: pointer;cursor: hand;color: black;font-family: Tahoma, Arial, Helvetica;font-size: 9pt;font-weight: bold;font-style: normal;

When I click in a link, the menu change the height and color...

Regards, João Rosa

}