Hi,

i am trying to edit the standart theme from silverstripe and i am pretty far right now - i only need to center the main navigation

http://www.p-wave.eu/Silverstripe/

... for now its left aligned .. i am a css beginner - anybody an idea how to make this work?

This should do the trick.

#navigation {
     text-align: center;
}

If not, you could try:

#navigation ul {
     margin: 0 auto;
}

both tricks not working ... :(

currently it looks

#Navigation {
	width: 800px;
	margin: 0 auto;
	height: 29px;
	overflow: hidden;
	background: #fff url(../images/nav_bg.gif) repeat-x;
}
#Navigation ul { 

	}

(on your Layout.css, goto line 130. you have and extra "/" for the comment.)

Try adding a width to #navigation ul, then try the codes again.

*edit*

#Navigation ul {
   text-align: center; 
}

...deleted the extra "/"....

#Navigation {
	width: 800px;
	margin: 0 auto;
	height: 29px;
	text-align:center;
/**	border: 1px solid;**/
	overflow: hidden;
	background: #fff url(../images/nav_bg.gif) repeat-x;
}
#Navigation ul { 
text-align: center; 
} 
#Navigation li { 
display: inline; 
}

...still not working ... :(

What happens when you do:

#Navigation ul {
text-align: center;
width: 500px;
}

or

#Navigation ul {
margin: 0 auto;
width: 500px;
}

..nothing - still the same.

#Navigation ul { 
margin: 0 auto; 
width: 500px; 
}

...it is smaller ... but still left centered... :(

Maybe:

#Navigation ul {
width: 100%;
}
#Navigation ul li {
margin: 0 auto;
}

*edit*
I'm not sure whats going on with your site. There's several other websites out there that will work with something as simple as:

#nav ul
{
margin: 0;
padding: 0;
list-style-type: none;
text-align: center;
}
#nav ul li { display: inline; }