I\'m using the following definitions (adapted from the CSS2 spec http://www.w3.org/TR/CSS21/cascade.html#specificity )
I guess that :first-line is more specific than just .content. So the first line of the text is pink, but the bullet of the list is green (and yellow on hover). Everything is good, as for me.
Imagine that the :first-line selector is just a nested text node selector, like:
-
The first line
The second line
It operates on the nested element, so it is more important than any other selector.