Differentiate the "Filter by Tag" Tab from Category Tabs

[raamdev]

Currently the "Filter by Tag" tab looks no different than the Category tabs:

Since "Filtering by Tag" is the primary way of filtering the KB Articles, I suggest that we differentiate this a bit by changing its color (you'll notice the Digital Ocean Community interface does this). Here's the tab with a background color of #FDFDFD:

It's a subtle change, but it goes a long way to indicating that the tab is special and that it does something.

[jaswrks]

Agreed. I'd call this ready to work on.