Originally Posted by speakingtohe
A simpler way to get started with the CSS if you use calibre at all is to use the internal viewer to inspect the CSS.
Select a block of the problem text and right click on it then click inspect.
Thanks for the tip about using "inspect" in Calibre to use the WebInspector. It's very helpful if you have multiple css files with possibly conflicting entries to be able to see which css selector is active for a particular section of text.