:root{
  --bg:#0b0d12; --panel:#12151d; --panel-2:#171b25; --line:#252b38;
  --text:#e8ecf4; --muted:#9aa4b6; --accent:#6ea8fe; --accent-2:#8b5cf6;
  --user:#1b2a44; --assistant:#151a24; --danger:#ff6b6b;
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;background:radial-gradient(1200px 600px at 20% -10%,#172038 0,transparent 60%),var(--bg);color:var(--text);
  font:15px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans SC",sans-serif;display:flex;flex-direction:column}
.topbar{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;
  padding:12px 20px;background:rgba(11,13,18,.82);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.brand{font-weight:700;letter-spacing:.2px;display:flex;align-items:center;gap:9px}
.dot{width:10px;height:10px;border-radius:50%;background:linear-gradient(135deg,var(--accent),var(--accent-2));box-shadow:0 0 14px #6ea8fe88}
.controls{display:flex;gap:8px;align-items:center}
select,input,textarea{font:inherit;color:var(--text);background:var(--panel-2);border:1px solid var(--line);border-radius:10px;outline:none}
select{padding:8px 10px;max-width:240px}
.icon-btn{width:38px;height:38px;border-radius:10px;border:1px solid var(--line);background:var(--panel-2);color:var(--text);cursor:pointer;font-size:17px}
.icon-btn:hover{border-color:#3a4258}
.messages{flex:1;overflow-y:auto;padding:28px 18px 8px;display:flex;flex-direction:column;gap:18px}
.hero{max-width:760px;margin:8vh auto 0;text-align:center;color:var(--muted)}
.hero h1{color:var(--text);font-size:30px;margin:0 0 8px}
.hero code{background:#ffffff10;padding:2px 6px;border-radius:6px}
.chips{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:22px}
.chip{cursor:pointer;padding:9px 14px;border-radius:999px;border:1px solid var(--line);background:var(--panel);color:var(--text)}
.chip:hover{border-color:var(--accent)}
.msg{max-width:820px;width:100%;margin:0 auto;display:flex;gap:12px}
.avatar{width:30px;height:30px;border-radius:9px;flex:none;display:grid;place-items:center;font-size:13px;font-weight:700}
.msg.user .avatar{background:#27406b}
.msg.assistant .avatar{background:linear-gradient(135deg,#2c3f6b,#4c2f74)}
.bubble{padding:12px 14px;border-radius:14px;border:1px solid var(--line);background:var(--assistant);white-space:pre-wrap;word-break:break-word;min-width:0;flex:1}
.msg.user .bubble{background:var(--user);border-color:#2c4166}
.bubble pre{background:#0a0d13;border:1px solid var(--line);border-radius:10px;padding:12px;overflow:auto;margin:8px 0;white-space:pre}
.bubble code{background:#ffffff12;padding:1px 5px;border-radius:5px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.92em}
.bubble pre code{background:none;padding:0}
.composer{padding:10px 18px 18px;position:sticky;bottom:0;background:linear-gradient(180deg,transparent,#0b0d12 30%)}
.composer-inner{max-width:820px;margin:0 auto;display:flex;gap:10px;align-items:flex-end;background:var(--panel);
  border:1px solid var(--line);border-radius:16px;padding:10px}
textarea#input{flex:1;resize:none;border:none;background:transparent;padding:8px 6px;max-height:180px;min-height:24px}
.send-btn,.stop-btn{border:none;border-radius:11px;padding:9px 16px;font-weight:600;cursor:pointer}
.send-btn{background:linear-gradient(135deg,var(--accent),var(--accent-2));color:#06101f}
.stop-btn{background:#3a1d24;color:#ffb3b3;border:1px solid #5a2a33}
.hint{max-width:820px;margin:7px auto 0;color:var(--muted);font-size:12px;text-align:center;min-height:18px}
.modal{position:fixed;inset:0;background:#0008;backdrop-filter:blur(4px);display:grid;place-items:center;z-index:50;padding:18px}
.modal[hidden]{display:none}
.modal-card{width:min(460px,100%);background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:20px}
.modal-card h2{margin:0 0 16px;font-size:18px}
.field{display:flex;flex-direction:column;gap:6px;margin-bottom:12px;color:var(--muted);font-size:13px}
.field input,.field select{padding:10px 12px}
.check{display:flex;gap:8px;align-items:center;color:var(--muted);font-size:13px;margin:4px 0 14px}
.modal-actions{display:flex;justify-content:flex-end;gap:8px}
.primary{background:linear-gradient(135deg,var(--accent),var(--accent-2));color:#06101f;border:none;border-radius:10px;padding:9px 16px;font-weight:700;cursor:pointer}
.ghost{background:var(--panel-2);color:var(--text);border:1px solid var(--line);border-radius:10px;padding:9px 14px;cursor:pointer}
.status{min-height:20px;color:var(--muted);font-size:12px;margin:12px 0 0}
.status.err{color:var(--danger)}
@media (max-width:640px){.brand{font-size:14px}.controls select{max-width:130px}.messages{padding:16px 10px}.bubble{padding:10px 12px}}