CSS classes for basic vertical navigation with sub-pages

I am having such a difficult time trying to figure out how to style my basic vertical navigation with drop-down sub-pages. 
I cannot find a simple tutorial or explanation for what CSS classes I need to target in order to change the style of my navigation.
All I can find so far is that I need to create a main.css file which I use to create a customized skin, but I can't get a straightforward answer about what to target for this specific look.

Image of what I want my nav to look like is attached- any help would be much appreciated from this newcomer!

Hello Sara,

Out navigation is based on several radControls. The particular mode you're talking about uses RadTreeView, thus some specific RadTreeView classes are set to it. The RadControl documentation contains reference for each of these classes, and should help you style your navigation. Please take a look at the article:

http://www.telerik.com/help/aspnet-ajax/treeview-appearance-css-selectors.html
 
Another way to achieve the desired navigation would be to create a simple user control (ascx file) and it it use RadPanelbar. This is navigation control again and bound to SitefinitySitemapDataSource it will have similar structure to what you're looking for. Here's a sample navigation with RadPanelBar:

http://www.telerik.com/help/wpf/radpanelbar-overview.html

http://demos.telerik.com/aspnet-ajax/panelbar/examples/overview/defaultcs.aspx