As threatened, NationStates has adopted "Rift" as the default theme! So now nothing is where you left it.
You can select a theme from your Settings page, so if you prefer an alternative, such as "Dark" or our previous default, "Century," you'll find those there.
The most noticeable difference is nation pages have pretty banners, which are gained by achieving things such as high levels of political corruption or pollution. If you can call those kinds of things achievements. Some people do. I'm not judging.
If you've been using Rift already (in beta), not much has changed. Although it is now possible to customize which events generate Notices! So if it's been annoying you that you get a Notice for every new telegram and issue, you can stop that. Look for a "Subscriptions" link above or below your Notices.
This kind of change often brings little bugs and quirks, because there are a lot of different web browsers and devices out there, and who has the time to test them all. Please report any problems you see in the Rift thread!