Hi, I am a new CM 1 user, just get started.
I have noticed that I can only edit CSS to change the look of widgets. Am i right? Therefor, I am wondering if there is a preset class or something else could let me to emphasize the current page of the Navigation Widget? For example, have a different background color. ( Not only the top level navigation element in the main navigation bar, but also in the secondary navigation.
I did a rough graphic. Hope it can show what I mean clearly.
Thanks a lot. 
Yes. CM1 puts the class “current” into all the navigation nodes in the widget that relate to the given page. In your case the nodes for “home” “about us” and “history” would all have the “current” class on them.
See extensive doc here, with examples of styling “current” in both rollover and vertical expanded nav elements.
http://help.percussion.com/cm1/Styling+Rollover+Navigation
http://help.percussion.com/cm1/Styling+Vertical+Navigation
The nav widgets put in extensive class information on levels and other information that is very useful for styling.
Thank you very much.
I have used that class. It works great.