[Moo] Can you use CSS3 in non-CSS3 browsers?

[cybervigilante]

I'm just learning MooTools. I see it uses CSS3 selectors. Does that
mean I can use CSS3 selectors even in browsers that don't support them
fully or well (like the nefarious IE), since MooTools is doing the
selecting? It seems logical to me, but I never assume the other guy is
using the same logic ;')