Hi @jeremiah01292, thanks for that. My site is hosted with 1and1 and I reissued the SSL but I was still seeing an issue with the CSS.
However, I installed the Live HTTP Headers Chrome extension and could see that the CSS assets were not being loaded (403 error). I then discovered that my themes folder permission was set to 750 and not the recommended 755!
Everything is back to normal now.
Hope this can help someone else ??