To align a div in the center, utilize CSS margins:
<div style="width: 800px; margin: 0 auto"></div>
Within that specific div, you can insert your navigation bar to occupy the available space effectively.
When it comes to the empty spaces on either side of the primary content, there are two potential approaches you can take.
You have the option to apply a background-image
to the body with top repeat-x
so that it looks like there is a horizontal bar spanning the entire width of your page.
Alternatively, you may separate the navigation from the main content, centering both using the method mentioned previously. Surround the top 'navigation' div with another div that has a 100% width. You can then customize this div according to your preferences. This approach offers the flexibility to adjust its position without the need to modify background images repeatedly.