body {
  margin: 0;
  padding: 0;

  font-family: serif;

  background-image: url("assets/paper.jpg");
  background-size: cover;
  background-position: center;

  color: #222;

  height: 100vh;

  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  width: 90%;
  max-width: 500px;

  background: rgba(255,255,255,0.75);

  padding: 32px;

  border: 2px solid #222;

  box-shadow: 0 0 20px rgba(0,0,0,0.3);

  text-align: center;
}

h1 {
  font-size: 2rem;
  margin-bottom: 24px;
}

.message {
  line-height: 1.8;
  margin-bottom: 24px;
}

input {
  width: 160px;

  font-size: 2rem;
  text-align: center;

  padding: 12px;

  border: 2px solid #222;

  background: #f8f1df;
}

button {
  display: block;

  margin: 24px auto 0;

  padding: 12px 24px;

  font-size: 1rem;

  background: #222;
  color: white;

  border: none;

  cursor: pointer;
}

#result {
  margin-top: 24px;

  font-size: 1.2rem;
  font-weight: bold;
}