#page_container{
width: 750px;
}

#left_column, #main_content, #sub_content{
display: block;
float: left;
}


#left_column{
width: 200px;
}


#main_content{
width: 550px;
}

#sub_content{
clear: left; /* push down to below left/center */
width: 750px;
margin-top: 5px;
}