Problem with collapsing content..

[Chandler_90]

I'm pretty confused right now..

I have a section on my website where i'm using css to colour a border over hovering..

It works fine on the machine I created it on at work.. but at home and on my mac it seems like the menu is collapsing upon hover..
However there is no collapse tag

Here is a section..

And here is the css..

Now I know the css ain't perfect but I'm just messing about at the min and plan to tidy up and optimise at a later date..

Thanks for the help..
Oh and for some reason this may only work in Firefox.. Its all screwed up in ie again.. lol..

*Edit*

Only seems to happen when I have the border in there.. perhaps the divs need to be resized..