CSS is outdated!
This message will appear on the homescreen when I've updated the site, but the CSS (code relating to visuals) is still using an older cached version.
Everything will still work fine, but certain things may not look correct until your browser updates the cache. You'll know when it happens when the message is gone.
If you're on PC, hit Ctrl+F5 on the homepage to update everything. Mobile users will have to wait.