/* ===== NLP Lab — shared styles (Class 8) · no external fonts ===== */
:root{
  --bg:#fbf6ef; --ink:#1f2430; --muted:#6b7280; --line:#e7ded2;
  --p:#6c5ce7; --b:#2d8cf0; --g:#15b884; --o:#ff8a3d; --pink:#ff5d8f; --yellow:#f5b50a;
  --card:#ffffff; --soft:0 10px 30px rgba(40,30,10,.08);
  --font:system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--font)}
a{color:var(--b);text-decoration:none}
.wrap{max-width:920px;margin:0 auto;padding:0 20px}

/* top bar */
.bar{display:flex;justify-content:space-between;align-items:center;gap:12px;
  padding:14px 20px;background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:9}
.bar .brand{font-weight:800}
.bar .brand span{color:var(--p)}
.bar a{font-size:14px;color:var(--muted);font-weight:600}
.bar a:hover{color:var(--ink)}

/* hero */
.hero{padding:40px 0 10px}
.pill{display:inline-block;background:#efe9ff;color:var(--p);font-weight:800;font-size:12px;
  letter-spacing:.08em;text-transform:uppercase;padding:5px 12px;border-radius:999px}
.hero h1{font-size:clamp(28px,5vw,40px);margin:14px 0 8px;line-height:1.12}
.hero p{font-size:18px;color:#444;max-width:680px;margin:0}

/* section bits */
h2{font-size:24px;margin:34px 0 10px}
h3{font-size:17px;margin:18px 0 8px}
.lead{color:#444;max-width:720px}
.muted{color:var(--muted)}
.divider{height:1px;background:var(--line);margin:30px 0}

/* lesson cards (hub) */
.cards{display:grid;grid-template-columns:repeat(2,1fr);gap:16px;margin-top:18px}
.lcard{display:block;background:var(--card);border:1px solid var(--line);border-radius:18px;
  padding:20px;box-shadow:var(--soft);transition:transform .15s,box-shadow .15s;color:inherit}
.lcard:hover{transform:translateY(-3px);box-shadow:0 16px 36px rgba(40,30,10,.14)}
.lcard .em{font-size:30px}
.lcard h3{margin:10px 0 4px;font-size:19px}
.lcard p{margin:0;color:var(--muted);font-size:14.5px}
.lcard .go{display:inline-block;margin-top:10px;color:var(--p);font-weight:800;font-size:14px}
.lcard .step{font-size:12px;font-weight:800;color:#fff;background:var(--p);border-radius:999px;
  padding:2px 9px;float:right}

/* playground panel */
.panel{background:var(--card);border:1px solid var(--line);border-radius:18px;padding:20px;
  box-shadow:var(--soft);margin:16px 0}
.panel .tlabel{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.row{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:10px 0}
input[type=text]{font:inherit;font-size:16px;padding:11px 13px;border:2px solid var(--line);
  border-radius:12px;width:100%;background:#fff;color:var(--ink)}
input[type=text]:focus{outline:none;border-color:var(--p)}

/* buttons */
.btn{font:inherit;font-weight:700;font-size:14.5px;padding:10px 16px;border-radius:12px;cursor:pointer;
  border:2px solid var(--line);background:#fff;color:var(--ink);transition:.15s}
.btn:hover{border-color:var(--p)}
.btn.on,.btn.primary{background:var(--p);border-color:var(--p);color:#fff}
.btn.b{background:var(--b);border-color:var(--b);color:#fff}
.btn.g{background:var(--g);border-color:var(--g);color:#fff}
.btn:disabled{opacity:.5;cursor:default}

/* token chips */
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:6px;min-height:30px}
.chip{display:inline-flex;flex-direction:column;align-items:center;gap:2px;
  padding:7px 11px;border-radius:11px;font-weight:700;color:#10243a;
  animation:pop .28s ease both}
.chip .id{font-size:10px;font-weight:800;color:#fff;background:rgba(0,0,0,.35);border-radius:6px;padding:0 5px}
.chip.sub{outline:2px dashed rgba(0,0,0,.18)}
@keyframes pop{from{opacity:0;transform:scale(.6) translateY(6px)}to{opacity:1;transform:none}}
.count{font-weight:800;color:var(--p)}

/* probability bars */
.pbars{display:flex;flex-direction:column;gap:8px;margin-top:8px}
.pbar{display:grid;grid-template-columns:120px 1fr 50px;align-items:center;gap:10px;font-size:14px}
.pbar .pl{font-weight:700}
.pbar .pt{height:16px;background:#f0ebe2;border-radius:8px;overflow:hidden}
.pbar .pf{height:100%;width:0;background:linear-gradient(90deg,var(--p),var(--b));border-radius:8px;
  transition:width .7s cubic-bezier(.3,1.2,.5,1)}
.pbar .pv{text-align:right;font-weight:800;color:var(--muted)}
.pbar.top .pl{color:var(--p)}
.pbar.click{cursor:pointer}
.pbar.click:hover .pt{outline:2px solid var(--p)}

/* quiz */
.quiz{background:#fff8ec;border:1px solid #f0d9a8;border-radius:16px;padding:16px 18px;margin:16px 0}
.quiz .q{font-weight:800;margin-bottom:10px}
.opts{display:flex;flex-wrap:wrap;gap:8px}
.opt{font:inherit;font-weight:700;padding:9px 14px;border-radius:11px;border:2px solid var(--line);
  background:#fff;cursor:pointer}
.opt.right{background:#e3f8ee;border-color:var(--g);color:#0c7a52}
.opt.wrong{background:#ffe7ec;border-color:var(--pink);color:#b5234a}
.fb{margin-top:10px;font-weight:700;min-height:22px}

/* callout: "in a real LLM" */
.callout{background:linear-gradient(180deg,#eef4ff,#f6f0ff);border:1px solid #d7defc;
  border-radius:16px;padding:16px 18px;margin:18px 0}
.callout b{color:var(--p)}
.callout .h{font-weight:800;color:var(--p);display:block;margin-bottom:4px}

/* comparison table */
.cmp{width:100%;border-collapse:collapse;margin-top:10px;font-size:15px;background:#fff;border-radius:14px;overflow:hidden}
.cmp th,.cmp td{border:1px solid var(--line);padding:10px 12px;text-align:left;vertical-align:top}
.cmp th{background:#f3eefe}
.cmp .tr{color:var(--o);font-weight:800}
.cmp .inf{color:var(--b);font-weight:800}

/* pipeline strip */
.pipe{display:flex;flex-wrap:wrap;gap:6px;align-items:center;margin:18px 0}
.pstep{background:#fff;border:1px solid var(--line);border-radius:12px;padding:9px 12px;font-weight:700;font-size:13.5px}
.pstep.lit{background:var(--p);border-color:var(--p);color:#fff;transform:translateY(-2px);transition:.2s}
.parrow{color:var(--p);font-weight:800}

/* generic flow / cards row */
.two{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.foot{color:var(--muted);font-size:13px;text-align:center;padding:34px 0}
.tag{display:inline-block;font-size:12px;font-weight:800;padding:3px 10px;border-radius:999px}
.tag.tr{background:#fff0e3;color:var(--o)}
.tag.inf{background:#e6f1ff;color:var(--b)}

/* multi-question quiz engine */
.qhead{font-size:12px;font-weight:800;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;margin-bottom:8px}
.qbar{height:6px;background:#f0d9a8;border-radius:4px;overflow:hidden;margin:4px 0 12px}
.qbar > span{display:block;height:100%;background:var(--o);transition:width .3s}
.qnav{margin-top:12px;display:flex;justify-content:flex-end}
.qdone{text-align:center;padding:10px}
.qdone .big{font-size:42px}
.exrow{display:flex;flex-wrap:wrap;gap:7px;margin:4px 0 2px}
.ex{font:inherit;font-size:13px;font-weight:600;padding:7px 11px;border-radius:10px;border:1px dashed var(--line);
  background:#fff;cursor:pointer;color:#444}
.ex:hover{border-color:var(--p);color:var(--p)}

/* section heading on hub */
.sec{font-size:13px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);
  margin:26px 0 4px;display:flex;align-items:center;gap:8px}
.sec .ln{flex:1;height:1px;background:var(--line)}

/* scatter plots (classification / clustering) */
.plot{width:100%;height:360px;background:#fff;border:1px solid var(--line);border-radius:16px;touch-action:none;cursor:crosshair}
.plot circle{transition:fill .35s, r .2s}
.plot .star{transition:cx .5s, cy .5s}
.legend2{display:flex;gap:16px;flex-wrap:wrap;margin-top:10px;font-size:14px}
.legend2 b{display:inline-flex;align-items:center;gap:6px;font-weight:700}
.legend2 .dot{width:12px;height:12px;border-radius:50%;display:inline-block}

/* pixel grid (vision) */
.pixwrap{display:flex;flex-wrap:wrap;gap:18px;align-items:flex-start}
.pix{display:grid;gap:2px;background:#ece5da;border-radius:10px;padding:4px}
.pix .cell{width:26px;height:26px;border-radius:4px;background:#fff;display:grid;place-items:center;
  font-size:10px;color:#b3aa9c;cursor:pointer;transition:background .12s}
.pix .cell.on{background:#1f2430;color:#fff}
.pix.fmap .cell{cursor:default;background:#f4f0ea}
.pix.fmap .cell.hot{background:var(--p);color:#fff}
.pix .cell.win{outline:3px solid var(--o);outline-offset:-1px;z-index:1}
.filt{display:grid;grid-template-columns:repeat(3,32px);gap:3px;margin-top:4px}
.filt .fc{width:32px;height:32px;display:grid;place-items:center;border-radius:6px;background:#efe9ff;
  font-weight:800;color:var(--p);font-size:13px}
.capt{font-size:12px;color:var(--muted);text-align:center;margin-top:4px;font-weight:700}

@media(max-width:680px){
  .cards,.two{grid-template-columns:1fr}
  .pbar{grid-template-columns:92px 1fr 44px}
}