ELU seems to get a textured background displayed right behind text elements:
(Or rather, it's the same background as on all the sites, but other sites that I've looked at have a plain color behind text.)
I wonder why, and whether there are any other sites where Time Travel Mode looks like this. (Edit: questions on https://judaism.stackexchange.com/ also look like this to me.) Is it a bug, either with the site or with my browser? Even taking into account that it's an April Fools' mode, I'm not sure that it's intentional for it to be so much harder to read posts on ELU or Mi Yodeya vs. on Stack Oveflow or on beta sites.