body {
    margin: 0; 
    padding: 0; 
}
header {
    background: #555; 
    color: white; 
    width: 100%; 
    text-align: center; 
    font-size: 300%; 
}

menu {
    width: 300px; 
    float: left; 
    background: #ccc; 
    height: 100vh; 
}

section.extras {
    width: 200px; 
    float: right; 
    border-left: 1px solid red; 
}

main {
    width: 480px; 
    float: left; 
}

footer {
    clear: both; 
    background: black; 
    font-weight: bold; 
    color: white; 
    text-align: center; 
}