These are the 'bare' essentials of the CSS centering hack: the width and the margin. If you don't specify a width, the margin trick won't work. If you don't specify the left and right margins as
auto the wrapper won't be centered.
You may say:
"But I specified a width: 100%!" ---
good for you and in truth, your wrapper IS being centered correctly. However, the contents of the wrapper (such as your navigation or content divs) are still aligned to the left since that is the default behavior for elements inside a block.
You can see this behavior by adding
border: 1px solid #F00 to your .wrapper div.
Now to fix your problem, you have to specify a width, preferably something slightly greater than the size (or percentage) of the content you put in your wrapper.
Try changing your .wrapper attributes to this:
.wrapper{
margin: 0 auto;
width:1015px;
}
Actually, you should start weaning yourself away from absolute positioning (there are exceptions) but your design can be implemented better without it... BAH alright, I'll still fix that search_bar.
Try this:
.search_bar{
float: right;
margin: 50px 80px 0 0;
}