@joli: Please share your site URL and let me know the color code that you want to change to then I can give you css. For example, you can change the color code in the following css and add in “Appearance => Customize => Theme Options => Custom CSS Options” to change the background color of the menu.
.nav-primary { background-color: #222; }
Note: Detail color options are there in pro version from where you can simply choose color from color picker to change the color of various elements from “Appearance => Customize => Color Options”. For more info about additional option in pro version, you can check out theme instructions page at http://catchthemes.com/theme-instructions/catch-responsive-pro/