:root{font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;line-height:1.5;color:#0f172a;background:#f1f5f9}*{box-sizing:border-box}body{margin:0;min-height:100vh}.app{max-width:720px;margin:0 auto;padding:1.5rem 1rem 2rem}h1{font-size:1.35rem;font-weight:600;margin:0 0 1rem}.chat-panel{background:#fff;border:1px solid #e2e8f0;border-radius:12px;box-shadow:0 1px 2px #0f172a0f;display:flex;flex-direction:column;min-height:420px;overflow:hidden}.messages{flex:1;padding:1rem;overflow-y:auto;display:flex;flex-direction:column;gap:.75rem;max-height:52vh}.bubble{max-width:92%;padding:.65rem .85rem;border-radius:10px;font-size:.95rem;white-space:pre-wrap;word-break:break-word}.bubble.user{align-self:flex-end;background:#2563eb;color:#fff}.bubble.assistant{align-self:flex-start;background:#f8fafc;border:1px solid #e2e8f0;color:#0f172a}.bubble.error{align-self:flex-start;background:#fef2f2;border:1px solid #fecaca;color:#991b1b}.composer{display:flex;gap:.5rem;padding:.75rem;border-top:1px solid #e2e8f0;background:#fafafa}.composer input{flex:1;border:1px solid #cbd5e1;border-radius:8px;padding:.55rem .75rem;font-size:1rem}.composer input:focus{outline:2px solid #93c5fd;outline-offset:0;border-color:#3b82f6}.composer button{border:none;border-radius:8px;padding:.55rem 1rem;font-size:.95rem;font-weight:600;background:#2563eb;color:#fff;cursor:pointer}.composer button:disabled{opacity:.55;cursor:not-allowed}.hint{margin-top:.75rem;font-size:.8rem;color:#64748b}