Grey lines

Dear all,

Iam just starting a new website and playing with wordpress for the first time.
till so far i can manage it very well.

But now i have one thing i cant find. and all codes i find on the internet didn`t work.
if you go to my site you will see above and below the header a grey line. and also one in the middle where the lower bar starts.

i just want this to be white or transparant. how can i do this ?

The page I need help with: [log in to see the link]