div's help

I would need help about this thing, in file new_index.html I have source
that has many div's, but what is wrong is that when I want but two div's
side by side id but one lower than first one, when I use css and but "top:
-50px" (that is the height of first div), it will leave free space bottom of
there, on Opera and Mozilla that works fine. I use "position: relative;",
and don't know how do to this whit absolute, or if I even can.

 

Can anybody help me? Is this even right place to ask this?

 

Margus