body {
    background-color: #f0f0f0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    min-height: 100vh;
    margin: 0;
    padding: 24px 16px 48px;
    box-sizing: border-box;
    font-family: sans-serif;
}

h1 {
    color: #333;
    margin-bottom: 16px;
    text-align: center;
}

main {
    width: 100%;
    max-width: 960px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
}

canvas {
    width: 100%;
    max-width: 800px;
    height: auto;
    aspect-ratio: 4 / 3;
    background-color: #fff;
    border: 1px solid #ccc;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
    touch-action: none;
    display: block;
    margin: 0 auto;
}