:root{font-family:-apple-system,BlinkMacSystemFont,"SF Pro Text",sans-serif;color:#111;background:#f5f6f8}body{margin:0;min-height:100vh;display:grid;place-items:center}.card{width:min(720px,92vw);background:#fff;border-radius:20px;padding:28px;box-shadow:0 10px 40px #0001}h1{margin-top:0}input{box-sizing:border-box;width:100%;padding:13px;border:1px solid #ddd;border-radius:12px;margin:7px 0}button{padding:12px 18px;border:0;border-radius:12px;background:#111;color:#fff;cursor:pointer}#messages{height:55vh;overflow:auto;border:1px solid #eee;border-radius:14px;padding:12px;margin:12px 0}.chat,.system{padding:7px 0}.system{color:#888}.send{display:flex;gap:8px}.send input{margin:0}.send button{white-space:nowrap}pre{white-space:pre-wrap;background:#f3f3f3;padding:12px;border-radius:10px}