Add blockquote style

Support blockquote

This blockquote is beautiful!! Daiki Nakashima

blockquote {
  position: relative;
  border-left: 6px solid rgba(227, 227, 227, 1);
  border-radius: 6px;
  padding: 8px;
  background-color: rgba(227, 227, 227, 0.4);
}
blockquote cite {
  display: block;
  font-size: 0.8rem;
  text-align: right;
  color: rgba(126, 128, 130, 1);
  padding-right: 10px;
}

I've updated the citation style throughout the site.
I've also experimented with adding support for the cite tag, but we'll see how much use it gets.
It's awesome seeing this site come together!