body {
    margin: 0;
    font-family: 'Segoe UI', sans-serif;
    background: url('https://images.unsplash.com/photo-1588776814546-ec7e00d6a243') no-repeat center center fixed;
    background-size: cover;
    color: #fff;
  }

  header {
    background-color: rgba(0, 119, 204, 0.9);
    padding: 20px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
  }

  header h1 {
    margin: 0;
    font-size: 2.5em;
  }

  nav {
    margin-top: 10px;
  }

  nav a {
    margin: 0 15px;
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    font-size: 18px;
  }

  nav a:hover {
    text-decoration: underline;
  }

  .main {
    text-align: center;
    padding: 100px 20px;
    background-color: rgba(0, 0, 0, 0.4);
  }

  .main h2 {
    font-size: 2em;
  }

  .main p {
    font-size: 18px;
    margin-bottom: 30px;
  }

  .btn {
    background-color: #28a745;
    color: white;
    padding: 12px 25px;
    font-size: 16px;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(0,0,0,0.2);
    transition: background 0.3s ease;
  }

  .btn:hover {
    background-color: #1e7e34;
  }

  @media (max-width: 600px) {
    header h1 {
      font-size: 1.8em;
    }
    nav a {
      display: block;
      margin: 10px 0;
    }
  }