header {
background-color:red;
color:white;
text-align:center;
padding:5px;
}

nav {
background-color:yellow;
padding:5px;
}

section {
padding:15px;
margin: 10px 10px 10px 10px;
width: 300px;
float: left;
}

aside{
background-color:blue;
padding:15px;
margin:10px 0px 10px 350px;
}

footer {
background-color:red;
color:white;
clear:both;
text-align:center;
padding:5px;
}

div#allcontent{
width: 840px;
margin-left:auto;
margin-right:auto;
}