#popup-overlay {
      position: fixed;
      top: 0; left: 0;
      width: 100%; height: 100%;
      background: rgba(0, 0, 0, 0.6);
      display: none;
      justify-content: center;
      align-items: center;
      z-index: 9999;
    }

    #popup {
      background: white;
      padding: 30px;
      border-radius: 10px;
      max-width: 400px;
      width: 90%;
      text-align: center;
      box-shadow: 0 0 20px rgba(0,0,0,0.3);
      animation: fadeIn 0.5s ease-in-out;
      position: relative;
    }

    #popup h2 {
      margin-top: 0;
      font-size: 22px;
    }

    #popup input[type="email"] {
      padding: 10px;
      width: 90%;
      margin: 15px 0;
      border: 1px solid #ccc;
      border-radius: 5px;
    }

    #popup button {
      padding: 10px 20px;
      background-color: #28a745;
      color: white;
      border: none;
      border-radius: 5px;
      cursor: pointer;
    }

    .close-btn {
      position: absolute;
      top: 10px; right: 15px;
      font-size: 20px;
      cursor: pointer;
      color: #888;
    }

    @keyframes fadeIn {
      from { opacity: 0; transform: scale(0.9); }
      to { opacity: 1; transform: scale(1); }
    }