Or maybe use a box shadow like: box-shadow: 0px 0px 15px 3px rgba(65,232,23,0.54); (for green)
OK, here's another try: brighter colors, no borders but colored shadows. This time I copied the styles to jsfiddle to let you try it yourself and fiddle around with it: http://jsfiddle.net/F984A/
Looks great! The dark works great with these colors.
Cor