refs ITC-257: added retina-ready grey arrow for homepage sidebar
refs ITC-257: updated mobile styles for homepage sidebar
refs ITC-257: stage 1 desktop styles updated (for smaller breakpoint)
refs ITC-257: large desktop styles for home sidebar added
fixes ITC-257: cleaned up extra unneeded styles
refs ITC-257: tweaks to home sidebar styles
finishes ITC-257: final OCD tweak to the home sidebar