canvas {
    border: 1px solid #000;
}
.centrer {
    margin: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
}

body {
    background-color: rgba(61, 55, 55, 0.829);
}