:root{--bg:#f6f7f9;--panel:#fff;--border:#e3e6ea;--text:#1c1f24;--muted:#6b7280;--accent:#0f6fff;--tool:#f0f3f8;--err:#b91c1c;--user:#e8f0ff}
*{box-sizing:border-box}
body{margin:0;font:15px/1.5 system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--text);background:var(--bg);display:flex;height:100vh}
body.login{align-items:center;justify-content:center}
.card{background:var(--panel);border:1px solid var(--border);border-radius:12px;padding:32px;width:340px;display:flex;flex-direction:column;gap:12px}
.card h1{margin:0;font-size:24px}
label{display:flex;flex-direction:column;gap:4px;font-size:13px;color:var(--muted)}
input,textarea{font:inherit;padding:8px 10px;border:1px solid var(--border);border-radius:8px;background:#fff;color:var(--text)}
button{font:inherit;padding:8px 14px;border:0;border-radius:8px;background:var(--accent);color:#fff;cursor:pointer}
a.button{display:block;text-align:center;padding:10px 14px;border-radius:8px;background:var(--accent);color:#fff;text-decoration:none;font-weight:500}
.small{font-size:12px}
button.link{background:none;color:var(--muted);padding:0;text-decoration:underline}
.muted{color:var(--muted)}.error{color:var(--err)}
#sidebar{width:260px;background:var(--panel);border-right:1px solid var(--border);display:flex;flex-direction:column}
.side-head{display:flex;justify-content:space-between;align-items:center;padding:14px 16px;border-bottom:1px solid var(--border)}
.brand{font-weight:600}
#new{padding:2px 10px;font-size:18px;line-height:1.2}
#chats{list-style:none;margin:0;padding:8px;overflow:auto;flex:1}
#chats li{padding:8px 10px;border-radius:8px;cursor:pointer;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;display:flex;justify-content:space-between;gap:6px}
#chats li:hover{background:var(--bg)}
#chats li.active{background:var(--user)}
#chats li .del{opacity:0;color:var(--muted);flex:none}
#chats li:hover .del{opacity:1}
.side-foot{padding:10px 16px;border-top:1px solid var(--border);font-size:12px;display:flex;justify-content:space-between}
main{flex:1;display:flex;flex-direction:column;min-width:0}
.banner{background:#fff7ed;border-bottom:1px solid #fed7aa;color:#9a3412;padding:8px 20px;font-size:13px}
#messages{flex:1;overflow:auto;padding:24px 0}
.empty{max-width:760px;margin:80px auto;text-align:center;color:var(--text)}
.msg{max-width:860px;margin:0 auto 18px;padding:0 20px}
.msg.user .bubble{background:var(--user);border-radius:12px;padding:10px 14px;display:inline-block;max-width:100%;white-space:pre-wrap}
.msg.user{text-align:right}
.msg .md p{margin:.4em 0}
.msg .md table{border-collapse:collapse;margin:8px 0;font-size:14px}
.msg .md th,.msg .md td{border:1px solid var(--border);padding:4px 10px;text-align:left}
.msg .md pre{background:#0f172a;color:#e2e8f0;padding:10px 12px;border-radius:8px;overflow:auto;font-size:13px}
.msg .md code{font-size:13px}
details.tool{background:var(--tool);border-radius:8px;margin:6px 0;font-size:13px}
details.tool summary{padding:6px 10px;cursor:pointer;color:var(--muted);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
details.tool pre{margin:0;padding:8px 10px;white-space:pre-wrap;word-break:break-all;max-height:320px;overflow:auto;font-size:12px}
details.tool.error summary{color:var(--err)}
.chart{margin:10px 0;border:1px solid var(--border);border-radius:10px;overflow:hidden;background:#fff}
.chart iframe{width:100%;height:460px;border:0;display:block}
.chart .cap{display:flex;justify-content:space-between;padding:6px 12px;font-size:13px;background:var(--tool)}
.chart .cap a{color:var(--accent)}
.thinking{color:var(--muted);font-size:13px}
.thinking::after{content:"…";animation:dots 1.2s steps(4,end) infinite}
@keyframes dots{0%{content:""}25%{content:"."}50%{content:".."}75%{content:"..."}}
.cost{font-size:11px;color:var(--muted);margin-top:4px}
#composer{display:flex;gap:8px;padding:14px 20px;border-top:1px solid var(--border);background:var(--panel)}
#composer textarea{flex:1;resize:none;max-height:200px}
#stop{background:var(--err)}