body {
  text-align: center;
}

.seat:nth-child(3),
.seat:nth-child(7) {
  margin-left: 10px;
}

#screen {
  border: 1px solid black;
  width: 275px;
  display: inline-block;
  padding-top: 20px;
  padding-bottom: 20px;
}

.occupied {
  color: red;
}

.selected {
  color: blue;
}

.seat {
  cursor: pointer;
}