body {
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f6f7fb;
    margin: 0;
    padding: 0;
  }
  
  .container {
    max-width: 480px;
    margin: 50px auto;
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
    text-align: center;
  }
  
  .logo {
    width: 300px;
    margin-bottom: 10px;
  }
  
  h1 {
    font-size: 1.5rem;
    color: #00a3c2;
    margin-bottom: 20px;
  }
  
  label {
    display: block;
    font-weight: 500;
    margin-bottom: 8px;
    color: #444;
    text-align: left;
  }
  
  input[type="number"] {
    width: 100%;
    padding: 10px;
    margin-bottom: 20px;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 6px;
  }
  
  button {
    padding: 12px 24px;
    font-size: 1rem;
    background-color: #00a3c2;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.3s ease;
  }
  
  button:hover {
    background-color: #00d2c9;
  }
  
  .result {
    margin-top: 20px;
    font-size: 1.1rem;
    color: #222;
  }
  
  .result p {
    margin: 6px 0;
  }
  
  .error {
    color: red;
    font-weight: bold;
  }