I added some custom error pages. You can check them out if you want for some reason. This change should have minimal impact on anybody.
If you fiddle hard enough, you'll note there's only pages for specific error codes. It would be nice to be able to redirect every error to a generic “error” page, but nginx doesn't seem to have this capability. Does anyone know of a decent hack to implement this? It's surprisingly difficult to search for—all my queries turned up loads of tutorials to set up 404 pages, something which is simple and well-documented.