html{
    background-color:yellow;
 font-family: sans-serif;
}

header{
    text-align:center;
	 height:30px;
}

aside{
float: left;
width:20%;
height:480px;
}
section{

    overflow:scroll;
    width:60%;
    height: 480px;
}
div{
    height:480px;
    width:20%;
    float:right;
}
footer{
text-align: center;
 height:30px;
clear:both;
}