body {
    margin: 0;
    padding: 20px;
    background-color: #f5f5dc; /* 生成り色 */
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    font-family: serif;
}

#stage {
    position: relative;
}

#sound-toggle {
    position: absolute;
    top: 8px;
    right: 8px;
    z-index: 1;
    border: 1px solid rgba(18, 18, 12, 0.45);
    background: rgba(245, 245, 220, 0.82);
    color: #12120c;
    font: 18px/1 serif;
    width: 36px;
    height: 36px;
    padding: 0;
    cursor: pointer;
    display: grid;
    place-items: center;
}

#sound-toggle:hover {
    background: rgba(255, 255, 238, 0.95);
}

#canvas-container {
    /* キャンバスを中央に */
}