I'm using Dark Reader (https://chrome.google.com/webstore/detail/dark-reader/eimadpbcbfnmbkopoojfekhnkhdbieeh) to invert colors on some websites. This works pretty well for Evernote, but some tweaks are still needed. Note that this hides the top three buttons (because they're images with light backgrounds) but they're still visible if you hover over them.