Make post change colour on mouse over

Hi all,

After designing a full website for a client he was over the moon with my result. However he took on board someone to build the actual site itself (the reason for why is beyond the scope of this email) and it was a total mess.

What I'm doing now is installing a super basic WP theme, and then over the next few months, I'll complete my CSS and Wordpress Theme tracks in order to deliver the original website design.

So, my question is this.

Once you go to http://www.copaseticresearch.co.uk and get past the Captcha the username & password are both: antfrogboy

You can see this try grid layout on the site. I would like each #post-area to change colour on mouseover. I really can't remember how to do this. I tried

#post-area a:hover { color: #ffffff;}

but there was nothing that came from it.

I'm a bit stumped. I know it's simple, but I just don't know what it is. Any help would be much appreciated!

Thanks in advance :)