Contribute panel styling on overview page

[iadawn]

From @slhenry comment in w3c/wai-quick-start#266.

On overview page, especially when there's only the first row of pages, the box stands out too much, I think. What about making the font smaller? and/or lighter?

[iadawn]

I am not sure that it would be good to reduce the size any further. Doing so will likely result in accessibility problems for some readers. Also, breaking the consistency with other pages may not be worth it.

I was wondering if this panel is needed on the overview page at all?

On the one hand there is not much content to be commented on, but it could be that this is the spot where people might suggest different areas to comment on. I remain hopeful :)