html, body {
      margin: 0; padding: 0; background: #333; color: #fff;
      font-family: Arial, sans-serif; height: 100%; overflow: hidden; user-select: none;
    }
    h1 { text-align: center; margin-bottom: 8px; }
    #ar-container {
      position: relative; width: 1080px; height: 600px; margin: 20px auto 0;
      border: 2px solid #555; background: #000; overflow: hidden;
    }
    #camera_feed {
      position: absolute; top: 0; left: 0; width: 100%; height: 100%;
      object-fit: cover; transform: scaleX(-1);
    }
    a-scene {
      position: absolute; top: 0; left: 0; width: 100%; height: 100%; z-index: 1;
    }
    #text-panel {
      position: absolute; top: 10px; right: 10px; left: auto; width: 240px;
      max-height: 580px; background: rgba(0, 0, 0, 0.7); color: #FFFFFF;
      padding: 10px; border-radius: 4px; overflow-y: auto; font-size: 14px;
      line-height: 1.4; display: none; z-index: 4;
    }
    #sidebar-container {
        position: absolute; top: 10px; left: 10px; width: 260px; height: 580px;
        background: rgba(0,0,0,0.7); border-radius: 4px; z-index: 2;
        display: none; padding: 8px; box-sizing: border-box; overflow-y: auto;
    }
    #sidebar-container h3 { text-align: center; margin: 4px 0 12px 0; font-size: 16px; }
    #organ-list {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 8px; list-style: none; margin: 0; padding: 0;
    }
    #organ-list li {
        cursor: pointer; height: 110px; border: 1px solid #555;
        border-radius: 4px; position: relative;
    }
    #organ-list li.all-organs-button {
      grid-column: 1 / -1; display: flex;
      justify-content: center; align-items: center;
      font-size: 18px; font-weight: bold;
    }
    #organ-list li:hover, #organ-list li.hand-hover {
        border-color: #fff; background-color: rgba(0, 150, 255, 0.3);
    }
    model-viewer {
      width: 100%; height: 100%; background-color: transparent;
    }
    #controls {
      margin: 12px auto; width: 640px; display: flex; justify-content: center; gap: 10px;
    }
    #controls button {
      padding: 8px 12px; font-size: 14px; cursor: pointer; background: #2196F3;
      color: #fff; border: none; border-radius: 4px;
    }
    #controls button:disabled { background: #555; cursor: not-allowed; }
    #output_canvas { display: none; }