Your first CSS selector—social.h2—is looking for the "social" element in the "h2", class, e.g.:
<social class="h2">
Class selectors are proceeded with a dot (.). Also, use a space () to indicate that one element is inside of another. To find an <h2> descendant of an element in the social class, try something like:
.social h2 {
color: pink;
font-size: 14px;
}
To get a better understanding of CSS selectors and how they are used to reference your HTML, I suggest going through the interactive HTML and CSS tutorials from CodeAcademy. I hope that this helps point you in the right direction.