Revert font size based on original template (rogchap.github.io)

Checked the css on the site we pulled from (rogchap.github.io)—he had
13.34px. I will look into picking up his mobile/tablet css for
cross-platform compatibility. For some reason that was lost in the
shuffle.
Revert "Revert font size based on original template (rogchap.github.io)"

This reverts commit 61643a4343281b5843888a980ede4d8f63e8c1a4.