Fixed css to show filter correctly

[Broele]

With the previous version, the two affected css lines were overridden by

#filter li {
    border: 2px solid #DDDDDD;
}

with this little change, the filtering tags are highlighted correctly.

[seblucas]

Indeed thanks a lot

[Broele]

It's a pleasure.
I just started to use cops for myself and this was the first thing I changed in the code. Maybe I will contribute some more in the future.