Rollover effect on phpBB

Is it easy to do?

[buksida]

I've seen a few phpBB boards with a rollover effect for each forum category that changes the shade of the background.

Does anyone know how to do this? Is it a simple modification of the CSS file?

[rogerd]

>>Is it a simple modification of the CSS file?

If there's a unique CSS class for the navigation elements, then creating the effect should be a matter of tweaking those settings.