How are you uploading it? Is your connection timing out perhaps?
In chrome, firefox press F12 and UI loads at bottom. If you select resources tab and frames this is all the assets being loaded. stylesheets , images, scripts, fonts, etc
You will usually see a red ! if something fails to load. At the moment, stylesheet has error message written saying it can't find that file - 404 error (which means it can't be found on server)