body {
  background:white;
  color:black;
  font-size:16px;
  font-family:sans-serif;
  padding:1em;
}
h1 {
  text-align:center;
  background:#669966;
  color:#AAFFAA;
  padding:1ex;
}
.centre { text-align:center; }
.right { text-align:right; }
.water { color:#333399; background:#AAAAFF; }
.fog { color:#CCCCCC; background:#666666; }
.desert { color:#666633; background:#FFFFAA; }
#tt { width:60%; margin:1ex 20%; }