:root{--ink:#17211b;--muted:#68736c;--paper:#f6f5ef;--card:#fff;--accent:#276749;--line:#dfe3dc;--user:#dcefe4}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}header{height:64px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 max(20px,calc((100% - 860px)/2));position:sticky;top:0;z-index:2}button{border:0;border-radius:12px;background:var(--accent);color:#fff;font:inherit;font-weight:700;padding:12px 18px;cursor:pointer}button:hover{filter:brightness(.95)}button.quiet{background:transparent;color:var(--muted);padding:8px 10px}.brand-mark{width:48px;height:48px;border-radius:15px;display:grid;place-items:center;background:var(--accent);color:#fff;font-size:24px;margin:auto}.brand-mark.small{display:inline-grid;width:31px;height:31px;border-radius:9px;font-size:15px;margin-right:10px}.chat-shell{max-width:860px;height:calc(100vh - 64px);margin:auto;display:flex;flex-direction:column;padding:0 20px}.messages{flex:1;overflow:auto;padding:38px 0 22px}.welcome{text-align:center;max-width:560px;margin:16vh auto 0}.welcome h1{font-size:clamp(28px,5vw,42px);line-height:1.15;margin-bottom:12px}.welcome p,.hint,.login-card p{color:var(--muted)}.message{display:flex;margin:0 0 20px}.message>div{max-width:78%;padding:13px 16px;border-radius:16px;white-space:pre-wrap}.message.user{justify-content:flex-end}.message.user>div{background:var(--user);border-bottom-right-radius:5px}.message.assistant>div{background:#fff;border:1px solid var(--line);border-bottom-left-radius:5px}.composer{background:#fff;border:1px solid #cfd6cf;border-radius:18px;padding:8px;display:flex;align-items:flex-end;box-shadow:0 8px 30px #17211b12}.composer:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px #2767491b}.composer textarea{flex:1;resize:none;border:0;outline:0;background:transparent;font:inherit;max-height:180px;padding:10px 12px}.composer button{width:45px;height:45px;padding:0;font-size:20px}.hint{text-align:center;font-size:12px;margin:8px 0 14px}.status{display:flex;gap:10px;align-items:center;color:var(--muted);font-size:14px;padding:4px 8px 12px}.status span{width:9px;height:9px;border-radius:50%;background:var(--accent);animation:pulse 1s infinite}.status button{margin-left:auto}.login{min-height:100vh;display:grid;place-items:center;padding:20px}.login-card{width:min(100%,390px);background:#fff;padding:38px;border:1px solid var(--line);border-radius:22px;box-shadow:0 18px 50px #17211b12;text-align:center}.login-card h1{margin:18px 0 4px}.login-card form{text-align:left;margin-top:24px}.login-card label{font-weight:700;font-size:14px}.login-card input{width:100%;font:inherit;padding:13px;margin:7px 0 14px;border:1px solid #bfc7bf;border-radius:10px}.login-card button{width:100%}.error{background:#fff1f0;color:#9f2720;padding:10px;border-radius:8px;margin-top:15px}@keyframes pulse{50%{opacity:.3}}@media(max-width:600px){.message>div{max-width:90%}.chat-shell{padding:0 12px}.messages{padding-top:22px}.login-card{padding:28px 22px}}