More typography tweaking. Also cleaning up some CSS redundancy in various Sass files.
Tweaking margins and padding in various lists and div boxes.
Made header fixed and transparent.Still need to find the correct header-height to bump the next div box below the header, but not sure yet how to do that while accommodating a roll-down menu for the mobile design.  Added copyright message to footer, which required erasing and rearranging the CSS that had applied only to the site map links. Created a 'h5' tag for copyright text in the footer. Removed footer's site map links in favor of email and social media icons (with text placeholders until I find or make icons).
Merging most recent changes from 'testing' branch.