body { font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif; padding: 40px; }
.box { max-width: 800px; }
button { padding: 10px 14px; margin-left: 8px; cursor: pointer; }
pre { background: #f5f5f5; padding: 12px; border-radius: 10px; margin-top: 16px; overflow:auto; }