css-parsing-problem

Hello,
for a couple of weeks the css validator is sending an answer for the request of validation with quite a lot of warnings. But this warnings must be wrong, cause they concern to the character of "cascading"! Why must i do set in every 'id' or 'class' every descriptor with its value always again, when it is actually inherited?
One of my css's is for example:
http://www.tfh-berlin.de/~loopy/exclude/style.css
I would be glad for an explanarion.
With regards (from Berlin-Germany!)
Thomas Ulrich