The community has spoken! We’ve stepped into the shadows and will now brainwash everyone to embrace it. This, however, only affects NEW registrants.
(Who enjoys light themes in 2018, anyway? Jk – about 38% apparently do!)
You can optionally RE-ENABLE light theme via the top-right hamburger (…but you shouldn’t):
^ To the left of LIGHT, you can also choose DARK, if you’ve been missing out!