/* Tam ekran düzeni */
    html, body {
      margin: 0;
      padding: 0;
      width: 100%;
      height: 100%;
      overflow: hidden;
      background-color: #000;
    }
    /* Yükleyici overlay */
    #loader {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-color: #000;
      display: flex;
      align-items: center;
      justify-content: center;
      z-index: 10;
    }
    /* Spinner animasyonu */
    .spinner {
      width: 50px;
      height: 50px;
      border: 5px solid rgba(255, 255, 255, 0.2);
      border-top-color: #fff;
      border-radius: 50%;
      animation: spin 1s linear infinite;
    }
    @keyframes spin { to { transform: rotate(360deg); } }
    /* model-viewer tam kaplama */
    model-viewer {
      width: 100%;
      height: 100%;
      --background-color: transparent;
    }