I’d vote for a browser cache clearing (Ctrl+F5 or equivalent). Or you could try another browser instance (I sometimes use a new ‘private’ browser instance to test things.)
I’d also look at the Network tab in Developer Tools (usually F12, or right-click anywhere in the page and select ‘Inspect Element’). After displaying the Network tab, refresh the page. Then look to see if the CSS elements are coming from the right domain/IP address. If they aren’t, there are changes required in your theme code. Maybe changing the theme to something else then back to the current theme would help.
Also slightly possible is your local DNS cache. At the command prompt (on a Windows box) use IPCONFIG /FLUSHDNS .Then restart the browser.