header.header {
    background-color: rgba(255, 0, 0, .2);
}
.column.main {
    background-color: rgba(255, 255, 0, .2);
}
.column.left {
    background-color: rgba(0, 255, 255, .2);
}
.column.right {
    background-color: rgba(0, 0, 255, .2);
}
footer.footer {
    background-color: rgba(0, 0, 0, .2);
}