body{
text-align: center;
margin: 0;
}

div#container{
width: 700px;
height: auto;
margin: 0 auto 0 auto;
text-align: left;
}

div#header{
width: 700px;
height: 124px;
background-color: silver;
}

div#nav{
width: 205px;
height: 400px;
float: left;
background-color: purple;
}

div#content{
width: 489px;
height: 400px;
float: left;
background-color: red;
}

div#footer{
width: 490px;
height: 50px;
text-align: center;
margin: 50px 0 30px 0;
background-color: yellow;
}