Changed out the 'many-line' and 'one-line' list classes: Made 'display: inline-block' the default for li, while just changing the display for the li within 'nav' in the mobile design. This allowed me to delete the 'lists.sass' page entirely. Worked on making a one-line header/nav display for non-mobile design, but eventually had to move the nav back inside the header's main container to achieve it. This breaks the full-width nav background on mobile screens, but I will try to fix it somehow.
Eliminated diagonal-striped background from '.social-media' in the footer. The stripes had too many breakpoints, both as PNG and as CSS. I saved the sass code in a new file called 'diagonal-lines-bg.sass' just in case I decide to try it again later.