body, html {
  height: 100%;
  margin: 0;
  color: white;
  background-color: black;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: 'Arial', sans-serif;
}

#countdown {
  text-align: center;
  padding: 20px;
  border: 2px solid white;
  border-radius: 10px;
}

#clock {
  font-size: 2em;
  font-weight: bold;
  background-color: #333;
  padding: 20px;
  margin-top: 20px;
  border-radius: 5px;
  display: inline-block;
}