* Make athens banner smaller
This helps people see that there is more content below the athens logo, otherwise
the most prominent thing they see is the next arrow >
and they miss our homepage content.
* Make home link friendly for previews
Right now when viewing a preview of our docs site, when I click on the home logo
I end up on our live site. This makes the home logo go to the root of the
current site instead, which is more friendly for testing docs locally
or previewing a PR.
