Hi,

You can find more information about how to customize the menu at here:

http://doc.essentialobjects.com/library/1/menucommon/styleandappearance/item_state.aspx
http://doc.essentialobjects.com/library/1/menucommon/styleandappearance/menu_item_styles.aspx
http://doc.essentialobjects.com/library/1/menucommon/styleandappearance/menu_group_appearance.aspx

A simple menu is usually customized with CSS only. Some advanced menu such as the Red Tab style, is created with a combination of CSS and images. For example, if you right click the Menu, then click Menu Builder, then select Look Items -> _TopLevelItem, then:

1. Expand NormalStyle, you will see "background-color: #cc0000", this is the red background color. Change that to any color you want;
2. Expand HoverStyle, you will see "background-color: #313131", this is the black background color. Change that to any color you want;
3. Expand LeftIcon, you will see both Url and HoverUrl are set. These are two images that are used to create the rounded corner on the left and right side of the menu item. If you change color for #1 and #2, then you will need to create two images matching those colors and specify them here;

For simple items that do not have round colors, you do not need to images. In the same window if you create Look Items -> _Default, you will see it has NormalStyle and HoverStyle set, but not LeftIcon and RightIcon. Those are for sub menu items which do not have round corners. Thus no images are used.

Hope this helps you to get some basic idea of how the menu works. The documentation should also cover a lot of other advanced customization options, so you may want to go over that to see what's available.

Thanks