I'd probably "center align" the webpage too.
That's not always a simple operation when using CSS and divs to layout your page. You can cheat and stick everything in a centered table but your tutor wouldn't like that approach very much.
Otherwise you can run the gauntlet with the:
margin-left: auto;
margin-right: auto;technique but not all browsers understand that.
Or finally, center the body using the:
text-align: center;rule, but don't forget that you'll have to set each div's CSS style to:
text-align: left;otherwise all text will center.