body { margin: 0; font-family: sans-serif; display: flex; flex-direction: column; align-items: center; }
    #plot { width: 800px; height: 600px; }
    #controls { padding: 12px; display: flex; gap: 8px; align-items: center; }
    button { padding: 8px 16px; cursor: pointer; }
    input { width: 80px; padding: 6px; }