Codecademy Sample Solution: Codeyear Center the Body

/* sample solution to style.css */
/* Layout */

body {
    font:normal 12px/1.6em Arial, Helvetica, sans-serif;
color:#2a3845;
background:#ffffff;
}

#wrapper {
    margin: 0 auto;
width: 632px;
}

#nav {
background:#06a;
text-align:right;
color:#f6dde3;
}

#header {

}

#bg {
height:36px;
    background:url('http://img840.imageshack.us/img840/9886/87926428.gif') repeat-x;
}

#main-content {
margin: 0 auto;
}

#main-image {
text-align: center;
}

#left-column {
    float: left;
width: 300px;
}

#right-column {
    float: right;
width: 270px;
}

.sidebar {
    background:url('http://img404.imageshack.us/img404/3092/shadowh.jpg') no-repeat top;
float: right;
    margin: 0 auto;
    width: 218px;
}

#footer {

}

/* Global Styling */

a:visited, a:link {
color:#a43b55;
text-decoration:underline;
background:none;
}

a:hover {
color:#a43b55;
text-decoration:none;
background:none;
}

h1 {
color:#7a2e40;
margin:0 0 10px;
padding-bottom:10px;
font:normal 17px Georgia, serif;
border-bottom:1px solid #efece7;
}

h2 {
color:#7a2e40;
margin:20px 0 10px;
padding-bottom:10px;
font:normal 17px Georgia, serif;
border-bottom:1px solid #efece7;
}

h3 {
color:#7a2e40;
margin:10px 0;
padding-bottom:10px;
font:bold 14px Arial, Helvetica, sans-serif;
border-bottom:1px solid #efece7;
}

ul {
padding:0;
margin:0 0 0 17px;
    list-style:square url('http://img525.imageshack.us/img525/1890/bulletr.gif');
}

.box {
background:#f7f7f7;
border:1px solid #f0e9eb;
padding:15px;
}

#nav a {
margin: 0 10px;
}

#nav a:visited, #nav a:link {
text-decoration:none;
color:#f6dde3;
}

#nav a:hover {
text-decoration:underline;
color:#f6dde3;
}

#logo {
margin-bottom:20px;
font:normal 18px Georgia, serif;
color:#fa7393;
}