h1, h2{
    font-size: 40px;
}

#first-section h2{
    background-color: red;
}

#first-section > h2{
    background-color: yellowgreen;
}


h2 ~ p {
    background-color: green;
    color: white;
}
h2 + p {
    background-color: blueviolet;
    color: white;
}

p::first-letter{
    color: orange;
    font-size: 90px;
}

p::before{
    content: "before";
}

p::after{
    content: "after";
}

p:hover{
    border:10px solid salmon;
}