body {
    margin: 0;
    overflow: hidden;
    background: black;
}

video {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transform: scaleX(-1);
    /* آینه‌ای */
}

canvas {
    position: fixed;
    top: 0;
    left: 0;
}