With just HTMLÂ and CSS!
I wanted to use the <marquee> element again, after all those years, just to find out that it is deprecated in all major browsers. But even if this would be the case, browsers would behave as if it would be any other element, not fancy animations at all but still very much usable. Not sure whether it is progressive enhancement or graceful degradation here.
Someone else came up with a better infinite marquee. It looks very nice, is responsive and using HTML and CSS only.