it uses alt-1 and alt-2 (so just change those two), or you can take advantage of the fact that it's all surrounded by a div named 'shout_content'
then your extra css can be
#shout_content .alt-1 { background: pink;}
#shout_content .alt-2 { background: blue;}
and you get what you want.. btw, i only show those colors for example.. you prolly want other stuff and also maybe not just the background colors too