body {
  text-align: center;
  font-family: sans-serif;
}

h1 {
  margin-top: 20px;
}

.timer {
  font-size: 48px;
  margin: 20px 0;
}

button {
  padding: 10px 20px;
  font-size: 16px;
  margin: 5px;
  cursor: pointer;
}