[css3-conditional] box-shadow example

In example 7 of "CSS Conditional Rules Module Level 3" [1], it claims that the @supports is grouping the 'color:white' rule with the 'box-shadow' rules, because the white text would be invisible if box-shadow wasn't supported. That would be true of 'text-shadow' (if the background and everything behind it was white or transparent), but the box-shadow in the example wouldn't make any difference. It goes around the outside of the box, and wouldn't be underneath the text normally (unless we are somehow assuming a negative indent, or a child element with negative margins or something). 

1) http://www.w3.org/TR/css3-conditional/#at-supports