body{text-align: center;}
#banner{background-color: tomato;width: 100%;height: 40px;}
#left{background-color: lightseagreen; width: 25%; height: 80%;float: left; margin-top: 10px; margin-bottom: 10px;}
#center{width: 50%; height: 80%; float: left;}
#right{background-color: lightseagreen; width: 25%; height: 80%;float: left; margin-top: 10px; margin-bottom: 10px;}
#footer{ background-color: darkgray; width: 100%; height: 40px; clear: both; }