body {
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-image: url('https://file.garden/aZiiX15cil6KFxpZ/mji.PNG');
    background-size: cover;
    background-repeat: no-repeat;
}

canvas {
    border: 2px solid #000;
    background-color: #fff;
}