h1{
    background-color:pink;
}
.a{
    background-color:violet;
}
.b{
    background-color:violet;
    width:100px;
    height:100px;
}
.c{background-color:pink;padding: 20px;}
.c .d{margin: 20px;border:1px solid black;
    background-color:lightgreen;padding: 20px;}