That looks like the CSS isn’t being applied. This is usually due to a url not being updated correctly, or occasionally trying to load assets over HTTPS but not having a valid certificate.
The best place to start is to troubleshoot by opening the developer tools for the browser and seeing what kinds of errors are in the console.
Spot on. It was a URL that wasn’t updating correctly. I made some changes to how the theme was calling the CSS and that solved the problem. Thanks for your help!