* {
    font-family: arial;
}

h2 {
    text-align: center;
}


p, button {
    /*color: red;*/
}


#outerDiv p {
    color: blue;
}


#innerDiv > p {
    color: green;
}


h3 + p {
    color: blue;
    text-decoration: underline;
}


p ~ h4 {
    color: orangered;
}