.whitebox {
  padding: 1em;
  background: white;
  color: black;
  border: 2px solid lightgray;
  border-radius: 10px;
}

.graybox {
  padding: 1em;
  background: gray;
  color: white;
  border: 2px solid black;
  border-radius: 10px;
}

.center {
  text-align: center;
}

mark {
  background-color: lightgray;
  color: black;
  font-weight: bold;
}

markcyan {
  background-color: cyan;
  color: black;
}