html { 
  background: url(background.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

.boxed {
  position: fixed;
  max-width: 16em;
  bottom: 1em;
  left: 1em;
  padding: 1em;
  border-radius: 0.5em;
  background: black;
  color: white;
  float: left;
  opacity: 0.6;
  text-align: center;
  font-family: "Arial", sans, sans-serif;
  font-size: 125%;
}