.on {
  background: red;
}

.off {
  background: gray;
}

div {
  margin-top: 20px;
}

#instructions {
  font-size: 20px;
}

.bit-number {
  font-size: 40px;
  margin: 2px;
  padding: 10px;
}

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

#timer {
  width: 200px;
  font-size: 60px;
  text-align: left;
}

#number {
  font-size: 60px;
}

.selected {
  background: blue;
}