Theming the Weather Block with CSS

Hi:

I'm making a Zen subtheme that has a dark-colored background. I need to be able to put the weather block on a light background for readability. This should be doable in the zen stylesheets using the .block class and the id of the weather block, but I've tried a number of different things and I can't seem to find the id to use. There's also no stylesheet included in the module with which to override the defaults that way. Many thanks to anyone who can point the way for me.