body {
      margin: 0;
      padding: 0;
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      background: linear-gradient(270deg, #001f3f, #0074D9, #00aaff);
      background-size: 600% 600%;
      animation: gradiente 15s ease infinite;
      color: white;
    }

    @keyframes gradiente {
      0% { background-position: 0% 50%; }
      50% { background-position: 100% 50%; }
      100% { background-position: 0% 50%; }
    }

    .container {
      max-width: 500px;
      background: rgba(0,0,0,0.6);
      padding: 40px;
      border-radius: 20px;
      text-align: center;
      box-shadow: 0 0 25px rgba(0,200,255,0.6);
      animation: fadeIn 1.5s ease-out;
    }

    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(30px); }
      to { opacity: 1; transform: translateY(0); }
    }

    h1 {
      font-size: 2rem;
      margin-bottom: 20px;
      color: #00cfff;
      text-shadow: 0 0 15px rgba(0,200,255,0.8);
    }

    input[type="text"] {
      width: 90%;
      padding: 12px;
      margin: 15px 0;
      border-radius: 8px;
      border: none;
      font-size: 1rem;
      text-align: center;
    }

    .btn {
      background: linear-gradient(135deg, #00cfff, #0077ff);
      border: none;
      border-radius: 50px;
      padding: 12px 30px;
      font-size: 1.1rem;
      color: white;
      cursor: pointer;
      transition: all 0.3s ease;
      box-shadow: 0 0 20px rgba(0,200,255,0.8), 0 0 40px rgba(0,200,255,0.4);
      display: inline-block;
      margin-top: 15px;
      text-decoration: none;
    }

    .btn:hover {
      transform: scale(1.08);
      background: linear-gradient(135deg, #00ffcc, #0077ff);
      box-shadow: 0 0 30px rgba(0,255,200,0.9), 0 0 60px rgba(0,200,255,0.7);
    }

    #greeting {
      margin-top: 20px;
      font-size: 1.2rem;
      color: #00ffcc;
      display: none;
    }