body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f9;
  margin: 0;
  padding: 0;
  color: #222;
}

.page {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 24px;
  box-sizing: border-box;
}

.card {
  width: 100%;
  max-width: 500px;
  background-color: #ffffff;
  padding: 24px;
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
}

h1 {
  margin-top: 0;
  font-size: 2rem;
  color: #333;
  text-align: center;
}

h2 {
  margin-top: 24px;
  margin-bottom: 12px;
  color: #333;
}

.intro {
  text-align: center;
  line-height: 1.5;
}

.notice {
  background: #eef4ff;
  border-left: 4px solid #007bff;
  padding: 12px;
  border-radius: 8px;
  margin: 16px 0;
  font-size: 0.95rem;
}

form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

label {
  font-weight: bold;
}

input[type="text"] {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 6px;
  font-size: 1rem;
  width: 100%;
  box-sizing: border-box;
}

input[type="submit"] {
  padding: 10px;
  border: none;
  background-color: #007bff;
  color: white;
  font-size: 1rem;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.2s ease-in-out;
}

input[type="submit"]:hover {
  background-color: #0056b3;
}

#result {
  margin-top: 20px;
  font-size: 1.1rem;
  font-weight: bold;
}