*{
    color: white;
}
body{
    background-color: #3d9b7d;
}
#green{
    background-color: rgba(0, 128, 0, 0.5);
}
#grey{
    background-color: hsl(0, 0%, 50%);
}
#blue{
    background-color: rgba(0, 0, 120);
}
li:nth-child(1),:nth-child(3),:nth-child(5){
    background-color: #ddd;
}
li:nth-child(2),:nth-child(4){
    background-color: #BBB;
}