body {
    background: #111;
    color: #fff;
    text-align: center;
  }
  canvas {
    background: #000;
    display: block;
    margin: 20px auto;
  }
  .modal {
    position: fixed;
    left: 0;
    top: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10;
  }
  .modal-content {
    background: #222;
    padding: 32px 40px;
    border-radius: 12px;
    box-shadow: 0 0 20px #000;
    text-align: center;
  }
  .level-btn {
    background: #fff;
    color: #111;
    border: none;
    padding: 12px 32px;
    margin: 12px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 20px;
    font-weight: bold;
    transition: background 0.2s, color 0.2s;
  }
  .level-btn:hover {
    background: #0f0;
    color: #111;
  }
  .hidden {
    display: none !important;
  }