Style the navbar

- Inspired by https://github.com/kevmo314/canigraduate.uchicago.edu
Give site basic UChicago color scheme; add favicon
Add some more styling

- Change background colors
Fix header styles

- Give header a fixed height

- Give header a padding equal to its bottom border height
Make header static; work on sticky footer
Make footer sticky
Add jQuery hack to make content-body tall enough

- Add jQuery hack to make content-body tall fill entire height between
  the bottom of the header and the top of the footer

- Ideally, remove this and use a pure CSS solution that preserves the
  sticky footer
Add container, logo, and border to footer
Make header taller