To see what faces are currently defined, and what they look like,
type @kbd{M-x list-faces-display}. It's possible for a given face to
look different in different frames; this command shows the appearance
-in the frame in which you type it.
+in the frame in which you type it. With a prefix argument, this
+prompts for a regular expression, and displays only faces with names
+matching that regular expression.
Here are the standard faces for specifying text appearance. You can
apply them to specific text when you want the effects they produce.