CSS problems in NS7 / Mozilla

This confuses me alot!

I tried to make a this site –> http://nr.nu “forward compatible”, yet still accesible for older browsers using all the tricks from webstandards.org.

It worked fine this spring, until Netscape released NS7 (built on the latest Mozilla which doesn’t work either). And I just can’t figure out why!!!

I use
@import “styles.css”;
to hide the styles from older browsers. Is that the catch?

Thanks in advance!

/Hannes