body {
  margin: 0;
  font-family: Arial, sans-serif;
  color: white;
  text-align: center;

  background: url('background.jpg') no-repeat center center fixed;
  background-size: cover;
}

.overlay {
  background: rgba(0, 0, 0, 0.5);
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

h1 {
  font-size: 3em;
  margin-bottom: 20px;
}

#countdown {
  font-size: 2em;
}