P.J.M. Smit said:
Thanks a thousend times over. It looks like I want it to be.
Problem is that I don´t understand what you did.
I would like to learn it too.
In the body I specified the common font-family, so I don't have to
specify for each element a font-family.
In the headline 'h1' you already specified text-align: center and in the
class .kop of h1 you specified margin-left: 5%. With other words the
content of h1 is centered and the whole h1 tag has a left margin of 5%
(margin creates a space between e.g. the #omheining and h1.kop). So I
removed the margin-left h1.kop.
I used float instead of margin-left for the img.logo, because I don't
know what the size of the browser window is, which the visitor have set,
it could be 800x600, 1024x800 or 1280x1024.
The same goes for the width and height for e.g. block elements (<div>).
That's why I didn't use margin and padding for the #linkerkolom.
I added display: block in .kop1, so that the menu buttons have the same
width. This way you haven't need to specify the width and height.
Also I placed the text-decoration: none in the .kop1, because you let
the visitor see what a link is.