lucy24 - 9:48 pm on Oct 31, 2012 (gmt 0)

Is .nav a class or an element? If it's a class, as the leading . implies, you also have to look at the elements you apply it to, and make sure your css overrides those elements' properties. (Hint: If you are using !important you are doing it wrong.) So not just
.nav
but also
p .nav
li .nav
p#superimportantheading .nav
and so on depending on your specific circumstances.

General principle: if you ever need
element1.class1 (for example "td.foobar")

to override
element2.class2 element1 (for example "tr.widget td")

make sure you include, by name,
element2.class2 element1.class1 ("tr.widget td.foobar")