header {
    background-color: #f00;
    color: #fff;
}
nav {
    background-color: #0f0;
    color: #fff;
}
article {
    background-color: #00f;
    color: #fff;
}
aside {
    background-color: #ff0;
    color: #ccc;
}
footer {
    background-color: #f0f;
    color: #ccc;
}
article header {
    background-color: #0ff;
    color: #999;
}