body {
   background: black;
   margin: 10px auto;
   width: 95%;
   font-size: 24px;
}

header, nav, #main, aside, footer {
   text-align: center;
}

header {
   background: cornflowerblue;
   line-height: 50px;
}

nav {
   background: khaki;
   float: left;
   width: 20%;
   line-height: 180px;
}

#main {
   background: darkseagreen;
   float: left;
   width: 60%;
   line-height: 180px;
}

aside {
   background: goldenrod;
   float: right;
   width: 20%;
   line-height: 180px;
}

footer {
   background: lemonchiffon;
   line-height: 50px;
}