Replacement for <center>
===

This has been asked before by other people, but I've never seen an adequate answer. Is there a valid replacement to the `<center>` tag? 

I know there's `margin: 0 auto;`, but that requires setting a width. There's also `align="center"`, but I believe that that's invalid code as well. 

Is there something as simple as `<center>` that's valid? There are rare occasions where I still end up using it, even though it is deprecated. Just today, I ended up using a `<center>` to center the one button that needed centered on a web page. Yes, I could have set the width and gave it `margin: 0 auto`, but that's a lot of work for centering one single element, and it dirties up my code, which I take pride in keeping orderly. I don't really understand why `<center>` was deprecated in the first place, if nothing has replaced it.

Thanks!