Most browsers these days now show websites as not secured when using HTTP. Loading the website from https://plaguefest.com results the page to load without any image content. Logging in from HTTP is also not recommend. The only thing that needs to be change is the CSS script, it appears to be loading content via HTTP, simply replacing that with HTTPS should solve that issue. I'm not familiar with Xenforo software, but if the CSS script is generated by Xenforo, I suspect changing the address from HTTP to HTTPS on the back-end should result the correct HTTPS address on the CSS script. If your using CloudFlare, which it appears that this website is using. You can enable "Always use HTTPS" under Crypto on the CloudFlare control panel. But I would recommend correcting the CSS script before enabling that. Thanks!