enable dark mode for join/reactivate modal #nomads

dark mode

add darkmode to #contactbox

Fix Swiftly login email colours #swiftly

fix color issue with email background

make CSS for sign up modal dark mode #nomads

Try to fix some dark mode color inversions on key background colors but all of it still gets overridden (thanks outlook and gmail) so going to leave it for now - email clients are seriously the worst, still. #creativity