I will throw some more in here as you start making changes you may want to center more items in the page:
/* Center Tables and set to 80% page width */
.kn-contenttable{
width:80%;
margin-left:auto;
margin-right:auto;
}
/* Center Menus */
.control {
position:relative;
text-align:center;
}
/* Center headers */
h1, h2, h3, h4, h5, h6 {
text-align:center;
}