According to the latest news at least. Includes font-size:0 per the original author of this mess.
.clearfix:after {
content:".";
display:block;
height:0;
font-size:0;
clear:both;
visibility:hidden;
}
.clearfix {display:inline-block;}
/* \\*/
* html .clearfix {height:1%;}
.clearfix {display:block;}
/* */Technical Preview 2 came close, but the latest nightly build is on the money!
This site has an entire history of Opera browsers testing Acid2. Note that IE7’s rendering is close to that of 2001’s Opera 6.
Opera 9 Technical Preview 2 rendering of the Acid2 test:
Acid2 allows at-a-glance testing of browsers against web standards, particularly the most needed and under-supported features of CSS2.1 and HTML4.01.