Actual (live) result in your browser:
Expected result (screen shot 300px wide, 68px tall):
References:
"sub
subscript the element"
CSS 1, section
5.4.4, vertical-align property
"sub
Lower the baseline of the box to the proper position
for subscripts of the parent's box"
CSS 2.1,
section 10.8.1, vertical-align property
Internet Explorer 8, NS 6.1, NS 6.2, NS 7.0, NS 7.1, NS 7.2, Firefox 1.5.x, Firefox 2.0.0.3, Firefox 3, Safari 2.0.4, Safari 3.0.4, Konqueror 3.5.5, Konqueror 4.1, Seamonkey 1.x, Seamonkey 2.x, K-meleon 1.x, Epiphany 2.14 all pass this test.
This bug has been reported at Opera BTS as bug DSK-250846.