You need to edit the menu content s to remove the sub level navigation, you cannot remove the sub level navigation from the css design.
you can change the background color on the design tab.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.