I thought you need to change the background color of the screen. Now I got what you are saying. You need to change the list item colors right ?
In this case definitely you need to customize the screen. You have to use a custom list as I mentioned in my blog, http://scn.sap.com/community/mobile/blog/2013/02/20/develop-hwc-app-with-customized-list then only you will get complete control over the screen. You can manipulate the code I mentioned to achieve this. http://jquerymobile.com/themeroller/index.php
- Midhun VP