Looking at the browser console I'm seeing a failure to load the installer.css file since it's not using a proper MIME type.
Refused to apply style from 'https://www.timnolte.com/wp-content/plugins/indieweb/assets/installer.css?ver=5.6.2' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.