<style>
    body {
      font-family: Arial, sans-serif;
      background: #0a1f3d;
      margin: 0;
      padding: 20px;
      color: #fff;
    }
    .container {
      max-width: 430px;
      margin: 40px auto;
      background: white;
      color: #000;
      padding: 30px;
      border-radius: 16px;
      box-shadow: 0 10px 40px rgba(0,0,0,0.3);
    }
    h1 { text-align: center; color: #0066cc; margin-bottom: 25px; }
    input {
      width: 100%;
      padding: 15px;
      font-size: 18px;
      border: 2px solid #ddd;
      border-radius: 10px;
      margin: 15px 0;
    }
    button {
      width: 100%;
      padding: 16px;
      font-size: 18px;
      background: #0066cc;
      color: white;
      border: none;
      border-radius: 10px;
      cursor: pointer;
    }
    .result {
      margin-top: 25px;
      padding: 20px;
      border-radius: 12px;
      display: none;
    }
    .success { background: #d4edda; color: #155724; }
    .error   { background: #f8d7da; color: #721c24; }
  </style>
