A fix for users experiencing issues related to low contrast design.
I'm not sure how to get this out to users experiencing issues, but I made a Stylebot style to fix contrast issues - you can use StyleBot on Chrome or Greasemonkey on Firefox*. Not sure about other browsers. It should ease eye strain but it isn't perfect by any stretch (and it isn't particularly pretty...). I mostly focused on the lessons b/c that's where I spend most of my time.
Style is here: http://stylebot.me/styles/4922
Link to Stylebot extension: https://chrome.google.com/webstore/detail/stylebot/oiaejidbmkiecgbjeifoejpgmdaleoha?hl=en
Link to Greasemonkey: https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/
*according to random people on Reddit, I didn't test personally