*, *::before, *::after {
      box-sizing: border-box;
    }

    :root {
      --primary-from: #4caf50;
      --primary-to: #2e7d32;
      --secondary-from: #039be5;
      --secondary-to: #0277bd;
    }

    body {
      margin: 0;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      font-family: 'Press Start 2P', monospace;
      color: #fff;
      background: linear-gradient(135deg, #0d0d0d 0%, #1a1a1a 100%);
      text-shadow: 0 1px 4px rgba(0, 0, 0, 0.6);
    }

    main.hero {
      flex: 1;
      padding: 4rem 1rem;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      text-align: center;
    }

    h1 {
      font-size: 2rem;
      margin: 0 0 1rem;
    }

    p.tagline {
      font-size: 0.9rem;
      opacity: 0.8;
      margin: 0 0 2rem;
    }

    .btn-group {
      display: flex;
      gap: 2rem;
      flex-wrap: wrap;
      justify-content: center;
    }

    a.btn {
      position: relative;
      display: inline-block;
      padding: 1rem 2.5rem;
      border-radius: 12px;
      text-decoration: none;
      font-size: 0.9rem;
      line-height: 1;
      transition: transform 0.2s ease, box-shadow 0.2s ease;
      user-select: none;
    }

    /* Primary (fresh install) */
    a.btn.primary {
      background: linear-gradient(45deg, var(--primary-from), var(--primary-to));
      box-shadow: 0 4px 14px rgba(76, 175, 80, 0.4);
      color: #fff;
    }

    /* Secondary (update) */
    a.btn.secondary {
      background: linear-gradient(45deg, var(--secondary-from), var(--secondary-to));
      box-shadow: 0 4px 14px rgba(3, 155, 229, 0.4);
      color: #fff;
    }

    a.btn.tertiary {
      background: linear-gradient(45deg, #ff9800, #f57c00);
      box-shadow: 0 4px 14px rgba(255, 152, 0, 0.4);
      color: #fff;
    }

    a.btn:hover {
      transform: scale(1.05);
    }

    a.btn:active {
      transform: scale(0.97);
    }

    footer {
      text-align: center;
      padding: 1rem 0;
      font-size: 0.65rem;
      background: #111;
      opacity: 0.8;
    }

    @media (max-width: 480px) {
      h1 {
        font-size: 1.4rem;
      }

      a.btn {
        width: 100%;
        text-align: center;
      }
    }