Do you use the developer tools available in various browsers?
Chrome, Firefox, Opera, and Safari (alpha order) all have developer tools - I'm partial to the webkit browsers Safari and Chrome but that could be because they are what I have mostly used.
Can you tell me where exactly to insert this in the css file? I can't find appropriate place.
On Mac OS X if one 'control-clicks' on an element in a web page(I believe this works for all 4 browsers I mentioned - I have not used Firefox firebug recently) a menu is brought up, one of the choices is 'inspect element' - click this and you will be shown the html and the css that is being applied to it. You can change things (the css or the html) and see the results. This should help you find the appropriate place.
Sorry I have too much on my plate right now to look at the code you are using.