p,button {
 /*color:red;*/
 font-family:Arial, Helvetica, sans-serif;
}

#outerDiv p {
    color:blueviolet;
}

#innerDiv > p {
    color:green;
}

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

p ~ h4 {
    color:red;
    text-decoration: dashed;
}