:root{
  --bg:#f5f7f9; --panel:#ffffff; --line:#e3e8ee; --text:#0f172a; --muted:#64748b;
  --accent:#0f9d6e; --accent-soft:#e8f7f1; --code-bg:#0f172a; --code-text:#e2e8f0;
  --radius:14px; --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;background:var(--bg);color:var(--text);
  font:15px/1.55 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  -webkit-font-smoothing:antialiased;
}
button{font:inherit;cursor:pointer}
.hidden{display:none !important}
.muted{color:var(--muted);font-size:13px;margin:0 0 10px}
.dot{width:7px;height:7px;border-radius:50%;background:#cbd5e1;display:inline-block}

/* ---------- login ---------- */
.login-body{display:grid;place-items:center;padding:24px;background:
  radial-gradient(900px 500px at 10% -10%,#e6f6ef 0%,transparent 60%),var(--bg)}
.login-card{width:100%;max-width:390px;background:var(--panel);border:1px solid var(--line);
  border-radius:20px;padding:30px;box-shadow:0 18px 50px -28px rgba(15,23,42,.35)}
.brand{display:flex;gap:12px;align-items:center;margin-bottom:26px}
.brand-mark{width:44px;height:44px;border-radius:12px;background:#0f172a;color:#34d399;
  display:grid;place-items:center;font:700 14px/1 var(--mono);letter-spacing:.5px}
.brand-mark.small{width:30px;height:30px;border-radius:9px;font-size:11px}
.brand h1{font-size:17px;margin:0;letter-spacing:.4px}
.brand-sub{margin:2px 0 0;font:12px var(--mono);color:var(--muted)}
label{display:block;font-size:12px;font-weight:600;letter-spacing:.3px;
  text-transform:uppercase;color:var(--muted);margin-bottom:7px}
.pw-row{display:flex;gap:8px}
input[type=password],input[type=text],textarea{
  width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:11px;background:#fbfcfd;
  font:inherit;color:var(--text);outline:none;transition:.15s}
input[type=password]:focus,textarea:focus{border-color:var(--accent);background:#fff;
  box-shadow:0 0 0 3px var(--accent-soft)}
.pw-row button{padding:0 20px;border:0;border-radius:11px;background:var(--accent);color:#fff;font-weight:600}
.pw-row button:disabled{opacity:.6}
.err{color:#dc2626;font-size:13px;min-height:18px;margin:10px 0 0}
.login-foot{display:flex;gap:7px;align-items:center;margin-top:18px;font:12px var(--mono);color:var(--muted)}
.login-foot .dot{background:var(--accent)}

/* ---------- shell ---------- */
.shell{display:flex;height:100%}
.sidebar{width:264px;flex:0 0 264px;background:var(--panel);border-right:1px solid var(--line);
  display:flex;flex-direction:column;padding:14px}
.side-head{display:flex;gap:10px;align-items:center;margin-bottom:14px;font-size:13px;letter-spacing:.4px}
.side-head .icon-btn{margin-left:auto;display:none}
.new-chat{padding:10px;border:1px dashed var(--line);background:#fbfcfd;border-radius:11px;
  font-weight:600;color:var(--text);margin-bottom:12px}
.new-chat:hover{border-color:var(--accent);color:var(--accent);background:var(--accent-soft)}
.conv-list{flex:1;overflow-y:auto;display:flex;flex-direction:column;gap:3px}
.conv{display:flex;gap:8px;align-items:center;padding:9px 10px;border-radius:10px;cursor:pointer;
  font-size:13.5px;color:#334155}
.conv:hover{background:#f1f5f9}
.conv.active{background:var(--accent-soft);color:#065f46;font-weight:600}
.conv span{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.conv .del{opacity:0;border:0;background:none;color:#94a3b8;font-size:15px;line-height:1}
.conv:hover .del{opacity:1}
.side-foot{border-top:1px solid var(--line);padding-top:10px;margin-top:10px;
  display:flex;align-items:center;justify-content:space-between;gap:8px}
.model-state{font:11.5px var(--mono);color:var(--muted);display:flex;gap:6px;align-items:center}
.model-state.on .dot{background:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.link-btn{border:0;background:none;color:var(--muted);font-size:12.5px;text-decoration:underline}

/* ---------- main ---------- */
.main{flex:1;display:flex;flex-direction:column;min-width:0}
.topbar{display:flex;gap:8px;align-items:center;padding:11px 16px;border-bottom:1px solid var(--line);
  background:rgba(255,255,255,.85);backdrop-filter:blur(8px)}
.ctl{border:1px solid var(--line);background:#fff;border-radius:9px;padding:6px 10px;
  font-size:12.5px;color:var(--text)}
.range-ctl{display:flex;gap:7px;align-items:center;font:12.5px var(--mono);color:var(--muted)}
.range-ctl input{width:86px;accent-color:var(--accent)}
.check-ctl{display:flex;gap:6px;align-items:center;cursor:pointer}
.check-ctl input{accent-color:var(--accent)}
.btn-ghost{border:1px solid var(--line);background:#fff;border-radius:9px;padding:6px 11px;font-size:12.5px;color:#475569}
.btn-ghost:hover{border-color:var(--accent);color:var(--accent)}
.spacer{flex:1}
.model-tag{font:11.5px var(--mono);color:var(--accent);background:var(--accent-soft);
  padding:4px 9px;border-radius:999px}
.icon-btn{border:0;background:none;font-size:16px;color:var(--muted);padding:4px 7px;border-radius:8px}
.icon-btn:hover{background:#f1f5f9}
.only-mobile{display:none}

.chat{flex:1;overflow-y:auto;padding:22px 16px 8px;scroll-behavior:smooth}
.empty{max-width:620px;margin:6vh auto;text-align:center}
.empty h2{font-size:22px;margin:0 0 6px;letter-spacing:.3px}
.empty p{color:var(--muted);margin:0 0 20px}
.chips{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}
.chip{border:1px solid var(--line);background:#fff;border-radius:999px;padding:8px 14px;
  font-size:13px;color:#334155}
.chip:hover{border-color:var(--accent);color:var(--accent)}

.messages{max-width:840px;margin:0 auto;display:flex;flex-direction:column;gap:18px}
.msg{display:flex;gap:11px}
.avatar{width:29px;height:29px;flex:0 0 29px;border-radius:9px;display:grid;place-items:center;
  font:700 10.5px/1 var(--mono)}
.msg.user .avatar{background:#e2e8f0;color:#475569}
.msg.bot .avatar{background:#0f172a;color:#34d399}
.bubble{flex:1;min-width:0;padding-top:3px}
.who{font-size:11.5px;text-transform:uppercase;letter-spacing:.6px;color:var(--muted);margin-bottom:4px}
.body{font-size:15px;line-height:1.62;overflow-wrap:anywhere}
.body p{margin:0 0 10px}
.body ul,.body ol{margin:0 0 10px;padding-left:22px}
.body li{margin:2px 0}
.body h1,.body h2,.body h3{font-size:15.5px;margin:16px 0 7px}
.body code{background:#eef2f6;padding:1.5px 5px;border-radius:5px;font:13px var(--mono)}
.body pre{background:var(--code-bg);color:var(--code-text);border-radius:12px;padding:0;
  overflow:hidden;margin:0 0 12px;border:1px solid #1e293b}
.pre-head{display:flex;justify-content:space-between;align-items:center;padding:7px 12px;
  background:#1a2438;font:11px var(--mono);color:#94a3b8}
.pre-head button{border:0;background:none;color:#94a3b8;font:11px var(--mono);cursor:pointer}
.pre-head button:hover{color:#34d399}
.body pre code{display:block;padding:12px 14px;background:none;overflow-x:auto;font:12.7px/1.55 var(--mono)}
.body a{color:var(--accent)}
.thinking{border-left:2px solid var(--line);padding-left:10px;color:var(--muted);
  font:12.5px/1.5 var(--mono);margin-bottom:9px;max-height:130px;overflow:auto;white-space:pre-wrap}
.cursor{display:inline-block;width:7px;height:15px;background:var(--accent);vertical-align:-2px;
  animation:blink 1s steps(2) infinite;border-radius:1px}
@keyframes blink{50%{opacity:0}}
.meta{font:11.5px var(--mono);color:#94a3b8;margin-top:6px}

/* ---------- composer ---------- */
.composer{padding:10px 16px 16px;background:linear-gradient(#f5f7f900,var(--bg) 40%)}
.input-wrap{max-width:840px;margin:0 auto;display:flex;gap:8px;align-items:flex-end;
  background:#fff;border:1px solid var(--line);border-radius:16px;padding:8px 8px 8px 14px;
  box-shadow:0 10px 30px -22px rgba(15,23,42,.4)}
.input-wrap:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
#input{flex:1;border:0;background:none;resize:none;padding:7px 0;max-height:190px;outline:none;font:inherit}
.send,.stop{width:36px;height:36px;flex:0 0 36px;border:0;border-radius:10px;background:var(--accent);
  color:#fff;font-size:16px;display:grid;place-items:center}
.send:disabled{background:#cbd5e1}
.stop{background:#dc2626;font-size:11px}
.hint{max-width:840px;margin:7px auto 0;font:11.5px var(--mono);color:#94a3b8}

/* ---------- modal ---------- */
.modal{position:fixed;inset:0;background:rgba(15,23,42,.35);display:grid;place-items:center;padding:20px;z-index:40}
.modal-card{width:100%;max-width:560px;background:var(--panel);border-radius:18px;padding:22px;
  box-shadow:0 30px 60px -30px rgba(15,23,42,.5)}
.modal-card h3{margin:0 0 4px;font-size:16px}
.modal-card textarea{font:13px var(--mono);margin-top:6px}
.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:14px}
.modal-actions #sysSave{border:0;background:var(--accent);color:#fff;border-radius:10px;padding:9px 16px;font-weight:600}

@media(max-width:820px){
  .sidebar{position:fixed;inset:0 auto 0 0;z-index:30;transform:translateX(-100%);
    transition:transform .22s ease;box-shadow:0 0 40px rgba(15,23,42,.2)}
  .sidebar.open{transform:none}
  .side-head .icon-btn{display:block}
  .only-mobile{display:block}
  .range-ctl,.check-ctl{display:none}
  .topbar{padding:9px 10px}
  .model-tag{display:none}
  .chat{padding:16px 12px 4px}
  .msg{gap:8px}
  .composer{padding:8px 12px 14px}
}