body {
    margin: 0;
    padding: 12px;
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f0f0;
    font-family: system-ui, sans-serif;
    color: #172033;
}

main {
    width: 400px;
    max-width: 100%;
    min-width: 0;
    text-align: center;
}

h1 {
    margin: 0 0 4px;
    font-size: 1.5rem;
}

p {
    margin: 0 0 12px;
    line-height: 1.4;
}

#canvas {
    display: block;
    width: 100%;
    max-width: 100%;
    height: auto;
    box-sizing: border-box;
    border: 1px solid #ccc;
    background-color: white;
    touch-action: none;
    -webkit-user-select: none;
    user-select: none;
}