Your css looks fine and the colour setting shows as white in Firebug - so I'd guess your Cufon is somehow overriding the css colour. Looks like you're using a Drupal plugin for Cufon - is it possible that somewhere in the settings for that the colour is being set, overriding the css?
If, for example, your Cufon code is like this:
Code:
Cufon.replace('h1',{fontFamily: 'Museo',color:'red' });
then h1 will be red whatever your css says.