body{font-family:sans-serif;padding:1rem}#tabBar{margin-top:1rem}.tab{display:inline-block;margin-right:.5rem;padding:.4rem .8rem;background:#ccc;border:none;border-radius:4px;cursor:pointer}.tab.active{background:#888;color:#fff}.view{display:none;margin-top:1rem}.view.active{display:block}canvas{border:1px solid #000}