body {
            margin: 0;
            overflow: hidden;
            background: #000;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        /* Camera Fullscreen Background */
        .input_video {
            position: absolute;
            top: 0;
            left: 0;
            width: 100vw;
            height: 100vh;
            object-fit: cover;
            transform: scaleX(-1);
            /* Gương lật video */
            z-index: 0;
            opacity: 0.6;
            /* Làm mờ nhẹ để nổi bật khối 3D */
        }

        canvas {
            position: absolute;
            top: 0;
            left: 0;
            display: block;
            z-index: 1;
        }

        #ui {
            position: absolute;
            top: 20px;
            text-align: center;
            z-index: 10;
            color: #333;
            width: 100%;
            pointer-events: none;
        }

        #status-box {
            font-size: 20px;
            font-weight: bold;
            color: #fff;
            background: rgba(0, 0, 0, 0.7);
            padding: 10px 25px;
            border-radius: 30px;
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
            transition: 0.3s;
            display: inline-block;
        }

        .instruction {
            margin-top: 10px;
            font-size: 15px;
            font-weight: 600;
            color: #fff;
            text-shadow: 1px 1px 4px rgba(0, 0, 0, 0.8);
        }

        /* Cursor ảo cho chế độ Lightbox */
        #cursor {
            position: absolute;
            width: 20px;
            height: 20px;
            background: rgba(255, 255, 255, 0.8);
            border: 2px solid #ffeb3b;
            border-radius: 50%;
            transform: translate(-50%, -50%);
            z-index: 100;
            pointer-events: none;
            display: none;
            box-shadow: 0 0 10px #ffeb3b;
        }