build skeleton for other prep units
wire up prep nav bar
wire up prep week index CTA
refactor prepnav and cta button colors into mix-ins
refactor colors and mixins to variables file
refactor breadcrumb css colors into a mixin
fix breadcrumb css bug
make hero mask week-dependent
make sections and lesson button colors week-dependent
make ctas follow week color scheme
fix project spacing
refactor CTAs into partials with proper coloring and edge case logic