:root{--bg:#f4f1ea;--surface:#fff;--user-bubble:#2f6f4e;--assistant-bubble:#fff;--border:#e2ddd0;--text:#2b2b2b;--muted:#7a7468;--accent:#2f6f4e}*{box-sizing:border-box}body,html{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Noto Sans Thai,sans-serif}.app{max-width:760px;margin:0 auto;min-height:100vh;display:flex;flex-direction:column;padding:24px 16px}.app-header h1{margin:0 0 4px;font-size:1.5rem}.app-header p{margin:0 0 16px;color:var(--muted);font-size:.9rem}.chat{background:var(--surface);border:1px solid var(--border);border-radius:14px;overflow:hidden}.chat,.messages{flex:1 1;display:flex;flex-direction:column}.messages{overflow-y:auto;padding:16px;gap:12px;min-height:360px}.empty-state{margin:auto;text-align:center;color:var(--muted);font-size:.9rem}.bubble{max-width:85%;padding:10px 14px;border-radius:14px;line-height:1.55;white-space:pre-wrap;word-wrap:break-word}.bubble.user{align-self:flex-end;background:var(--user-bubble);color:#fff;border-bottom-right-radius:4px}.bubble.assistant{align-self:flex-start;background:var(--assistant-bubble);border:1px solid var(--border);border-bottom-left-radius:4px}.bubble.assistant :first-child{margin-top:0}.bubble.assistant :last-child{margin-bottom:0}.bubble.assistant a{color:var(--accent)}.bubble.assistant pre{background:#f6f4ee;padding:10px;border-radius:8px;overflow-x:auto}.bubble.assistant hr{border:none;border-top:1px solid var(--border)}.bubble.error{align-self:flex-start;background:#fdecea;border:1px solid #f5c2bd;color:#a3261c}.typing{align-self:flex-start;color:var(--muted);font-size:.85rem;padding:4px 6px}.composer{display:flex;gap:8px;padding:12px;border-top:1px solid var(--border);background:var(--surface)}.composer textarea{flex:1 1;resize:none;border:1px solid var(--border);border-radius:10px;padding:10px 12px;font:inherit;outline:none;max-height:140px}.composer textarea:focus{border-color:var(--accent)}.composer button{border:none;background:var(--accent);color:#fff;border-radius:10px;padding:0 18px;font-weight:600;cursor:pointer}.composer button:disabled{opacity:.5;cursor:not-allowed}