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

nav {
background-color: yellow;
padding: 7px;
}

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

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

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

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