Style blockquote citations

It’s a little thing really, but something I’d like to see rolled into the theme. When styling blockquote with a child cite the following code will provide a better experience for users:

blockquote cite {
  display: block;
}

blockquote cite::before {
   content: "\2014 \0020";
}

This moves a citation onto its own line and precedes it with an emphasized dash and a space. Learned that little trick from Feeling Responsive, which was inspired my Michael Rose.