[css-page-floats] float: center?

Hi,

I'm just learning HTML and CSS, and it strikes me as odd that there is no
float: center command. Intuitively, this would center a box in its
containing element and also cause it to take the width of its contained
text. I'm guessing this question arises out of ignorance, but why doesn't
such a command exist? Perhaps it could be implemented in a future version
of HTML?

I spent some time reading forums, and I found a functional workaround
involving three layers of divs. This seems unnecessarily complex.

Thanks,
Sam