body {
    margin: 0;
    padding: 0;
    background: #f8f9fa;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    font-family: Arial, Helvetica, sans-serif;
}
#canvas-container {
    width: 100%;
    max-width: 760px;
}
canvas { display: block; }