CSS instead of a marquee tag?

The marquee tag is a non-standard proprietary tag that doesn't work in all browsers. In fact, it works in very few browsers. For the browsers that don't recognize the tag, it's simply text on the page and not even in a "paragraph". Some browsers don't even display the text. They ignore the tag and it's contents.

There is no CSS that replaces what the marquee tag does (making text move). However, text can be made to move in a variety of ways, animated GIF's being one way. Javascript being another. So, if you care to learn that language, you can make text move. Or, you can search for a pre-written script to do it.