Css from zenbased theme not getting processed
This is a good checklist for resolving css bugs - I would suggest two more that I've used when stuck on css bugs that may help you resolve this quicker next time.


Check the element in firebug or developer tools to confirm whether the CSS file you think should be loaded actually is and what css styles are actually being applied to it. In this case, you could have determined that the file was loaded but the styles weren't so you could isolate your debugging to the syntax of the statement.
Try using an external validator on your css file, like:


http://jigsaw.w3.org/css-validator/

Most of the feedback from this will be noise but it may highlight syntax errors in your file.