Sass:
    $barva1: red
    $barva2: greenyellow
    $barva3: skyblue
    $barva4: black
CSS:
    .p1
    color: $barva1
    background-color: $barva2
    .p2
    color: $barva2
    background-color: $barva1
    .p3
    color: $barva3
    background-color: $barva4
    .p4
    color: $barva4
    background-color: $barva3