Depends what you mean by 'standards'. 7 & 8 support more of CSS 2.1 than the other browsers. I believe support for CSS3 is lacking because they didn't want to

Depends what you mean by 'standards'. 7 & 8 support more of CSS 2.1 than the other browsers. I believe support for CSS3 is lacking because they didn't want to write to a draft, and then have to support no-longer-standard extensions when the draft changed.