/* =========================================================================
   How LLMs Work — shared stylesheet
   Restrained, editorial design system: near-black ink, one disciplined
   indigo accent used only where it carries meaning, hairline borders,
   calm motion.
   ========================================================================= */

:root{
  --bg:#ffffff;
  --bg-soft:#fafbfc;
  --panel:#f4f5f8;
  --ink:#15171c;
  --text:#3a3f48;
  --muted:#767c88;
  --line:#e8e9ee;
  --line-strong:#d6d8e0;
  --accent:#4f46e5;
  --accent-ink:#4036c4;
  --accent-weak:#eef0fd;

  --radius:12px;
  --radius-sm:8px;
  --shadow-sm:0 1px 2px rgba(20,22,28,.04), 0 2px 6px rgba(20,22,28,.06);
  --shadow:0 14px 40px -18px rgba(20,22,28,.22);

  --maxw:880px;
  --measure:68ch;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,"Helvetica Neue",sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;font-family:var(--font);color:var(--text);background:var(--bg);
  line-height:1.7;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
  font-size:17px;
}
h1,h2,h3,h4{color:var(--ink);margin:0 0 .5em;line-height:1.15;letter-spacing:-.021em;font-weight:680}
h1{font-size:clamp(2.1rem,5vw,3.1rem);font-weight:720;letter-spacing:-.03em}
h2{font-size:clamp(1.55rem,3.4vw,2.15rem);font-weight:700;letter-spacing:-.025em}
h3{font-size:1.16rem;font-weight:640}
h4{font-size:1rem;font-weight:640}
p{margin:0 0 1.05rem}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
::selection{background:var(--accent-weak)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:4px}
img{max-width:100%}

.accent-text{color:var(--accent)}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.lead{font-size:clamp(1.08rem,1.6vw,1.22rem);color:var(--text);font-weight:400;line-height:1.6}
.small{font-size:.85rem}
.muted{color:var(--muted)}
.center{text-align:center}
main.lesson .wrap>p,main.lesson .wrap>.lead{max-width:var(--measure)}
.center .lead{margin-left:auto;margin-right:auto}

/* ----------  Top scroll-progress line  ---------- */
#progress{
  position:fixed;top:0;left:0;height:2px;width:0%;z-index:60;background:var(--accent);
  transition:width .1s linear;
}

/* ----------  Course header  ---------- */
header.top{
  position:fixed;top:0;left:0;right:0;z-index:50;
  display:flex;align-items:center;justify-content:space-between;gap:14px;
  padding:13px 24px;background:rgba(255,255,255,.82);backdrop-filter:saturate(180%) blur(12px);
  border-bottom:1px solid var(--line);
}
header.top .brand{font-weight:640;font-size:.95rem;display:flex;gap:9px;align-items:center;text-decoration:none;color:var(--ink);white-space:nowrap;letter-spacing:-.01em}
header.top .brand:hover{text-decoration:none}
header.top .brand .bdot{width:10px;height:10px;border-radius:50%;background:var(--accent)}
.course-mid{display:flex;align-items:center;gap:13px}
.lesson-no{font-size:.8rem;font-weight:500;color:var(--muted);white-space:nowrap;font-variant-numeric:tabular-nums}
.dots{display:flex;gap:7px}
.dot-step{width:6px;height:6px;border-radius:50%;background:var(--line-strong);transition:.3s}
.dot-step.on{background:var(--ink)}
.dot-step.cur{background:var(--accent);transform:scale(1.5)}
.home-link{font-size:.82rem;color:var(--muted);text-decoration:none;padding:6px 12px;border-radius:8px;border:1px solid var(--line);white-space:nowrap}
.home-link:hover{background:var(--bg-soft);color:var(--ink);text-decoration:none}
@media(max-width:680px){.dots{display:none}}

/* ----------  Lesson rhythm  ---------- */
main.lesson{padding:96px 0 32px;min-height:62vh}
.kicker{
  display:inline-flex;align-items:center;gap:10px;font-size:.76rem;font-weight:600;
  text-transform:uppercase;letter-spacing:.13em;color:var(--muted);margin-bottom:18px;
}
.kicker .num{
  display:grid;place-items:center;min-width:24px;height:24px;padding:0 6px;border-radius:6px;
  background:var(--accent);color:#fff;font-size:.78rem;font-weight:600;letter-spacing:0;
}

/* ----------  Layout / cards  ---------- */
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:18px;align-items:stretch}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
@media(max-width:760px){.grid2,.grid3{grid-template-columns:1fr}}
.card{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:22px}
.demo{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:26px;margin-top:26px;box-shadow:var(--shadow-sm)}
.demo .demo-tag{
  display:inline-flex;gap:8px;align-items:center;font-size:.72rem;font-weight:600;
  text-transform:uppercase;letter-spacing:.12em;color:var(--accent);margin-bottom:8px;
}
.demo .demo-tag::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--accent)}
.note{font-size:.84rem;color:var(--muted);line-height:1.55}
.step-label{font-size:.72rem;font-weight:600;text-transform:uppercase;letter-spacing:.1em;color:var(--accent);margin-bottom:8px}
.analogy{
  background:var(--bg-soft);border:1px solid var(--line);border-left:2px solid var(--accent);
  padding:16px 20px;border-radius:var(--radius-sm);margin:20px 0;
}
.analogy b{color:var(--ink)}

/* form bits */
textarea,input[type=text]{
  width:100%;font-family:var(--font);font-size:1rem;padding:12px 14px;border-radius:var(--radius-sm);
  border:1px solid var(--line-strong);background:var(--bg);color:var(--ink);resize:vertical;
}
textarea:focus,input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-weak)}
button.ui{
  cursor:pointer;border:1px solid var(--ink);padding:10px 16px;border-radius:var(--radius-sm);
  font-weight:600;font-size:.9rem;color:#fff;background:var(--ink);transition:opacity .15s,background .15s,transform .1s;
}
button.ui:hover{background:#000}
button.ui:active{transform:translateY(1px)}
button.ui:disabled{opacity:.32;cursor:not-allowed}
button.ui.alt{background:var(--bg);color:var(--ink);border-color:var(--line-strong)}
button.ui.alt:hover{background:var(--bg-soft)}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
label.slider{display:flex;flex-direction:column;gap:7px;font-size:.84rem;font-weight:500;color:var(--muted)}
label.slider b{color:var(--ink);font-variant-numeric:tabular-nums}
input[type=range]{accent-color:var(--accent);width:240px;max-width:100%}
.btn{
  display:inline-flex;align-items:center;gap:8px;cursor:pointer;border:1px solid var(--ink);
  padding:12px 22px;border-radius:var(--radius-sm);font-weight:600;font-size:.98rem;color:#fff;
  background:var(--ink);text-decoration:none;transition:background .15s,transform .1s;
}
.btn:hover{background:#000;text-decoration:none}
.btn:active{transform:translateY(1px)}
.btn.ghost{background:var(--bg);color:var(--ink);border-color:var(--line-strong)}
.btn.ghost:hover{background:var(--bg-soft)}

/* ----------  Home hero  ---------- */
.hero{
  min-height:88vh;display:flex;flex-direction:column;justify-content:center;align-items:center;
  text-align:center;padding:120px 24px 80px;position:relative;
}
.hero h1{max-width:16ch;margin-bottom:.35em}
.hero .lead{max-width:40ch;margin:0 auto 2rem;color:var(--muted)}
.hero .meta{font-size:.85rem;color:var(--muted);margin-top:22px}
.teaser{
  display:inline-flex;flex-wrap:wrap;justify-content:center;gap:8px;margin-top:34px;
  font-size:.8rem;color:var(--muted);
}
.teaser span{padding:5px 11px;border:1px solid var(--line);border-radius:999px;background:var(--bg)}
.teaser .arr{border:none;padding:5px 2px;color:var(--line-strong)}

/* ----------  Contents (editorial index)  ---------- */
.toc{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px;margin-top:28px;text-align:left}
.toc a{
  display:flex;gap:16px;align-items:flex-start;text-decoration:none;color:inherit;background:var(--bg);
  border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px;transition:border-color .15s,box-shadow .15s,transform .1s;
}
.toc a:hover{border-color:var(--line-strong);box-shadow:var(--shadow-sm);transform:translateY(-2px);text-decoration:none}
.toc .ic{font-size:1.05rem;font-weight:700;color:var(--accent);font-variant-numeric:tabular-nums;line-height:1.6;min-width:24px}
.toc .t{font-weight:640;color:var(--ink);margin:0 0 2px}
.toc .d{font-size:.86rem;color:var(--muted);line-height:1.5}

/* ----------  Tokenizer  ---------- */
#tok-out,#count-toks{display:flex;flex-wrap:wrap;gap:5px;margin-top:14px;min-height:42px}
.tk{padding:5px 9px;border-radius:6px;font-size:.9rem;font-weight:500;border:1px solid var(--line);animation:fade .2s ease}
.tk.word{background:var(--panel);color:var(--ink)}
.tk.punct{background:var(--bg);color:var(--muted)}
.tk.split{background:var(--accent-weak);color:var(--accent-ink);border-color:#dcdcfb}
.tk.cont{position:relative;margin-left:3px}
.tk.cont::before{content:"";position:absolute;left:-4px;top:50%;width:3px;height:1px;background:var(--line-strong);transform:translateY(-50%)}
.stat{display:inline-flex;gap:7px;align-items:baseline;margin-right:22px}
.stat b{font-size:1.6rem;color:var(--ink);font-variant-numeric:tabular-nums;font-weight:700}

/* ----------  Embedding map  ---------- */
#map-wrap{position:relative;width:100%;aspect-ratio:16/10;background:var(--bg-soft);
  border-radius:var(--radius-sm);overflow:hidden;border:1px solid var(--line)}
#map-svg{position:absolute;inset:0;width:100%;height:100%}
.word-dot{position:absolute;transform:translate(-50%,-50%);cursor:pointer;font-size:.8rem;font-weight:600;
  padding:4px 10px;border-radius:999px;white-space:nowrap;transition:transform .15s,box-shadow .15s,opacity .2s;
  border:1px solid var(--line);background:var(--bg);color:var(--ink);box-shadow:var(--shadow-sm)}
.word-dot:hover{transform:translate(-50%,-50%) scale(1.08)}
.word-dot.dim{opacity:.32}
.word-dot.sel{transform:translate(-50%,-50%) scale(1.12);box-shadow:0 0 0 3px var(--accent-weak),var(--shadow-sm)}
.legend{display:flex;flex-wrap:wrap;gap:16px;margin-top:14px;font-size:.8rem;color:var(--muted)}
.legend span{display:inline-flex;gap:7px;align-items:center}
.legend i{width:9px;height:9px;border-radius:50%;display:inline-block}
.vec{font-family:var(--mono);color:var(--ink);font-size:.9em}

/* ----------  Word-similarity score-cards (lesson 3)  ---------- */
.sim-pick{display:flex;flex-direction:column;gap:8px;margin:4px 0 16px}
.sim-row{display:flex;gap:10px;align-items:flex-start}
.sim-lab{font-size:.7rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);font-weight:700;width:54px;flex:none;padding-top:7px}
.sim-chips{display:flex;gap:6px;flex-wrap:wrap}
.sim-chip{cursor:pointer;padding:5px 12px;border-radius:999px;border:1px solid var(--line-strong);background:var(--bg);font-size:.85rem;font-weight:600;color:var(--text)}
.sim-chip.on.a{background:var(--accent);border-color:var(--accent);color:#fff}
.sim-chip.on.b{background:#0e7490;border-color:#0e7490;color:#fff}
.sim-cards{display:flex;flex-direction:column;gap:9px;margin-top:4px}
.sim-trait .t{font-size:.8rem;color:var(--ink);font-weight:600;margin-bottom:3px}
.sim-bar{height:11px;border-radius:6px;background:var(--panel);position:relative;margin:2px 0}
.sim-bar > span{position:absolute;left:0;top:0;bottom:0;border-radius:6px;transition:width .4s ease}
.sim-bar.a > span{background:var(--accent)}
.sim-bar.b > span{background:#0e7490}
.sim-meter{margin-top:16px}
.sim-meter-track{height:16px;border-radius:8px;background:var(--panel);overflow:hidden}
.sim-meter-fill{height:100%;width:0;border-radius:8px;background:var(--accent);transition:width .5s ease}
.sim-score{margin-top:7px;color:var(--ink);font-variant-numeric:tabular-nums}

/* ----------  Attention  ---------- */
#att-sentence{display:flex;flex-wrap:wrap;gap:7px;margin:18px 0;font-size:1.1rem}
.aw{padding:5px 10px;border-radius:6px;font-weight:500;transition:background .5s ease,color .3s;
  background:rgba(79,70,229,0);border:1px solid transparent}
.aw.focus{border-color:var(--accent);border-style:dashed}
#att-bars{display:flex;flex-direction:column;gap:7px;margin-top:14px}
.abar{display:grid;grid-template-columns:104px 1fr;gap:12px;align-items:center;font-size:.85rem}
.abar .lbl{text-align:right;color:var(--muted);font-weight:500}
.abar .track{height:14px;background:var(--panel);border-radius:7px;overflow:hidden}
.abar .fill{height:100%;width:0;border-radius:7px;transition:width .8s cubic-bezier(.2,.8,.2,1);background:var(--accent)}

/* ----------  Prediction  ---------- */
.pbars{display:flex;flex-direction:column;gap:8px;margin-top:8px}
.pbar{display:grid;grid-template-columns:124px 1fr 48px;gap:12px;align-items:center;font-size:.88rem}
.pbar .w{font-weight:600;text-align:right;color:var(--ink)}
.pbar .track{height:20px;background:var(--panel);border-radius:6px;overflow:hidden}
.pbar .fill{height:100%;width:0;border-radius:6px;transition:width .5s ease;background:#a5a0f0}
.pbar.top .fill{background:var(--accent)}
.pbar .pct{font-variant-numeric:tabular-nums;color:var(--muted);font-weight:500}
#story-out{font-size:1.12rem;line-height:1.85;min-height:60px;background:var(--bg-soft);
  border:1px solid var(--line);border-radius:var(--radius-sm);padding:16px 18px;margin-bottom:14px;color:var(--ink)}
#story-out .new{background:var(--accent);color:#fff;padding:1px 5px;border-radius:4px;animation:fade .3s ease}
.cursor{display:inline-block;width:2px;height:1.05em;background:var(--accent);vertical-align:-2px;
  animation:blink 1.1s steps(2) infinite;margin-left:1px}
@keyframes blink{50%{opacity:0}}

/* ----------  Pipeline  ---------- */
.pipe{display:flex;align-items:stretch;flex-wrap:wrap;margin-top:14px;justify-content:center}
.stage{flex:1;min-width:128px;max-width:180px;text-align:center;padding:18px 12px;border-radius:var(--radius);
  border:1px solid var(--line);margin:5px;transition:all .35s;background:var(--bg)}
.stage.active{border-color:var(--accent);background:var(--accent-weak)}
.stage .si{display:grid;place-items:center;width:30px;height:30px;margin:0 auto 10px;border-radius:50%;
  background:var(--panel);color:var(--ink);font-weight:600;font-size:.9rem;transition:.35s}
.stage.active .si{background:var(--accent);color:#fff}
.stage .st{font-weight:640;font-size:.9rem;color:var(--ink)}
.stage .sd{font-size:.74rem;color:var(--muted);margin-top:3px}
.loopback{text-align:center;margin-top:16px;font-size:.92rem;color:var(--muted)}
.loopback b{color:var(--ink)}
.loop-out{font-size:1.35rem;font-weight:600;color:var(--ink);background:var(--bg-soft);border:1px solid var(--line);
  border-radius:var(--radius-sm);padding:16px 18px;min-height:62px;margin:0 auto 16px;max-width:520px;text-align:center}
.loop-out .new{background:var(--accent);color:#fff;padding:1px 7px;border-radius:6px;animation:fade .3s ease}

/* ----------  Training-data pipeline (lesson 8)  ---------- */
.pipeline-steps{display:flex;gap:8px;flex-wrap:wrap;margin:18px 0}
.pstep{cursor:pointer;padding:8px 14px;border-radius:999px;font-weight:600;font-size:.82rem;
  border:1px solid var(--line-strong);background:var(--bg);color:var(--muted);font-variant-numeric:tabular-nums}
.pstep.on{background:var(--ink);color:#fff;border-color:var(--ink)}
#tdp-tokens{display:flex;flex-wrap:wrap;gap:5px}
.ex-head{display:grid;grid-template-columns:1fr 36px auto;gap:10px;font-size:.7rem;text-transform:uppercase;
  letter-spacing:.08em;color:var(--muted);font-weight:600;margin-bottom:8px}
.ex-head .a{text-align:right}
.ex-table{display:flex;flex-direction:column;gap:6px}
.ex-row{display:grid;grid-template-columns:1fr 36px auto;gap:10px;align-items:center}
.ex-ctx{font-family:var(--mono);font-size:.84rem;background:var(--panel);border:1px solid var(--line);
  border-radius:var(--radius-sm);padding:7px 11px;text-align:right;color:var(--ink);
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.ex-arrow{text-align:center;color:var(--muted)}
.ex-tgt{font-family:var(--mono);font-size:.84rem;background:var(--accent);color:#fff;border-radius:var(--radius-sm);
  padding:7px 12px;font-weight:600;justify-self:start;white-space:nowrap}

/* ----------  Multi-page training pipeline (lesson 8)  ---------- */
.corpus{display:grid;grid-template-columns:repeat(auto-fill,minmax(238px,1fr));gap:10px;margin-top:16px}
.cpage{border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--bg-soft);
  padding:11px 13px;font-size:.9rem;line-height:1.5;color:var(--text)}
.cpage .csrc{display:block;font-size:.67rem;text-transform:uppercase;letter-spacing:.06em;
  color:var(--muted);margin-bottom:6px;font-weight:600}
.cpage .jl{display:block;color:var(--muted);text-decoration:line-through;
  text-decoration-color:var(--line-strong);font-size:.8rem;line-height:1.45}
.cpage .kl{display:block;margin-top:5px;background:var(--accent-weak);color:var(--accent-ink);
  border-radius:4px;padding:3px 6px}
.cpage .ctx{color:var(--ink);font-weight:600}
.cpage .nxt{background:var(--accent-weak);color:var(--accent-ink);border-radius:4px;padding:0 5px;font-weight:600}
.tally-head{font-size:.7rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);font-weight:600;margin-bottom:8px}
.ex-row.key .ex-ctx{border-color:var(--accent);color:var(--ink);font-weight:600}
.ex-row.key .ex-tgt{box-shadow:0 0 0 3px var(--accent-weak)}
/* step 6 — tune the dials */
.tune-q{font-size:1.25rem;font-weight:600;color:var(--ink);text-align:center;margin:2px 0 16px}
.tune-guess{display:inline-block;min-width:62px;background:var(--panel);border:1px solid var(--line-strong);
  border-radius:var(--radius-sm);padding:1px 10px;color:var(--muted);transition:background .3s,color .3s,border-color .3s}
.tune-guess.ok{background:var(--accent);border-color:var(--accent);color:#fff}
.dial-label{text-align:center;font-size:.82rem;color:var(--text);margin-bottom:8px}
.dials{display:flex;gap:16px;justify-content:center;margin:2px 0 18px;flex-wrap:wrap}
.dial{width:48px;height:48px}
.dface{fill:var(--bg-soft);stroke:var(--line-strong);stroke-width:2}
.dptr{transform-box:view-box;transform-origin:20px 20px;transition:transform .45s cubic-bezier(.3,.9,.4,1)}
.dptr line{stroke:var(--accent);stroke-width:3;stroke-linecap:round}
.tune-note{margin-top:13px;font-size:.9rem;color:var(--text);min-height:1.5em}

/* ----------  Neural-network visual (lesson 5)  ---------- */
#net-wrap{background:var(--bg-soft);border:1px solid var(--line);border-radius:var(--radius-sm);padding:12px 10px}
#net-svg{width:100%;height:auto;display:block}
.net-edge{stroke:var(--line);stroke-width:.3;transition:stroke .3s}
.net-edge.active{stroke:var(--accent);stroke-width:.55}
.net-node{fill:var(--line-strong);transition:fill .3s}
.net-node.active{fill:var(--accent)}
.net-cols{display:flex;justify-content:space-between;margin-top:6px;font-size:.7rem;color:var(--muted);
  text-transform:uppercase;letter-spacing:.06em}

/* ----------  Learning-loop / loss (lesson 9)  ---------- */
.train-grid{display:grid;grid-template-columns:1.25fr 1fr;gap:22px;align-items:start;margin-top:6px}
@media(max-width:700px){.train-grid{grid-template-columns:1fr}}
.loss-box{background:var(--bg-soft);border:1px solid var(--line);border-radius:var(--radius-sm);padding:16px 18px}
.loss-num{font-size:2.1rem;font-weight:700;color:var(--ink);font-variant-numeric:tabular-nums;line-height:1.1}
.loss-num small{font-size:.78rem;font-weight:500;color:var(--muted);display:block;text-transform:uppercase;letter-spacing:.08em}
#loss-hill{width:100%;height:112px;margin-top:10px;display:block}
.hill-curve{fill:none;stroke:var(--line-strong);stroke-width:1.5;vector-effect:non-scaling-stroke;stroke-linejoin:round}
.hill-ball{fill:var(--accent);transition:cx .55s cubic-bezier(.45,1.5,.55,1),cy .55s cubic-bezier(.45,1.5,.55,1)}

/* ----------  Scaling dial (lesson 11)  ---------- */
#scale-out{background:var(--bg-soft);border:1px solid var(--line);border-radius:var(--radius-sm);padding:18px;margin-top:14px}
.scale-name{font-weight:700;color:var(--ink);font-size:1.05rem;margin-bottom:10px}
.scale-rows{display:flex;flex-direction:column;gap:0;font-size:.9rem}
.scale-rows>div{display:flex;justify-content:space-between;gap:16px;border-bottom:1px solid var(--line);padding:7px 0}
.scale-rows span{color:var(--muted)}
.scale-rows b{color:var(--ink);text-align:right}
.scale-can{margin-top:13px}
.scale-can span{font-size:.7rem;text-transform:uppercase;letter-spacing:.08em;color:var(--accent);font-weight:600}
.scale-can p{margin:4px 0 0;color:var(--text)}
.scale-track{height:8px;background:var(--panel);border-radius:6px;overflow:hidden;margin-top:14px}
.scale-track .fill{height:100%;width:0;background:var(--accent);border-radius:6px;transition:width .35s ease}

/* ----------  Predict-the-word game (lesson 10)  ---------- */
.skills{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:20px}
.skill{font-size:.72rem;font-weight:600;text-transform:uppercase;letter-spacing:.08em;
  padding:6px 13px;border-radius:999px;border:1px solid var(--line-strong);background:var(--bg);
  color:var(--muted);display:inline-flex;align-items:center;gap:7px;opacity:.5;
  transition:opacity .35s,background .35s,color .35s,border-color .35s}
.skill::before{content:"";width:7px;height:7px;border-radius:50%;background:var(--line-strong);transition:background .35s}
.skill.on{opacity:1;background:var(--accent-weak);color:var(--accent-ink);border-color:#dcdcfb}
.skill.on::before{background:var(--accent)}
.game-q{font-size:1.22rem;font-weight:600;color:var(--ink);line-height:1.65;text-align:center;margin:6px 0 18px}
.game-q .blank{display:inline-block;min-width:82px;padding:0 8px;text-align:center;font-weight:700;
  color:var(--accent);border-bottom:2px solid var(--accent);transition:color .3s}
.game-opts{display:flex;gap:10px;flex-wrap:wrap;justify-content:center;margin-bottom:6px}
.opt{cursor:pointer;font-family:var(--font);padding:10px 18px;border-radius:var(--radius-sm);font-weight:600;
  font-size:.96rem;border:1px solid var(--line-strong);background:var(--bg);color:var(--ink);
  transition:background .2s,border-color .2s,color .2s,opacity .2s,transform .1s}
.opt:hover:not(:disabled){border-color:var(--accent);background:var(--accent-weak)}
.opt:active:not(:disabled){transform:translateY(1px)}
.opt:disabled{cursor:default}
.opt.ok{background:#e9f7ee;border-color:#7fce9b;color:#1f7a3d}
.opt.no{background:#fef3f2;border-color:#fda29b;color:#b42318}
.opt.faded{opacity:.4}
.game-end{font-size:1.08rem;font-weight:600;color:var(--ink);text-align:center;line-height:1.65;padding:8px 0}
/* "watch a rule lock in" — streaming-documents demo (same lesson) */
.lock-doc{background:var(--bg-soft);border:1px solid var(--line);border-radius:var(--radius-sm);
  padding:14px 16px;font-size:1.02rem;line-height:1.6;color:var(--ink);min-height:62px;margin-bottom:18px}
.lock-doc .src{display:block;font-size:.66rem;text-transform:uppercase;letter-spacing:.06em;
  color:var(--muted);font-weight:600;margin-bottom:6px}
.lock-doc .hit{background:var(--accent-weak);border-radius:4px;padding:1px 5px}
.lock-doc .verb{color:var(--accent);font-weight:700}
.lock-tabs,.mm-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:6px}
.ltab,.mm-tab{cursor:pointer;font-family:var(--font);padding:7px 14px;border-radius:999px;font-weight:600;font-size:.84rem;
  border:1px solid var(--line-strong);background:var(--bg);color:var(--muted);
  transition:background .2s,color .2s,border-color .2s}
.ltab:hover,.mm-tab:hover{border-color:var(--accent);color:var(--ink)}
.ltab.on,.mm-tab.on{background:var(--ink);color:#fff;border-color:var(--ink)}

/* ----------  Context window (lesson 13)  ---------- */
#ctx-forgotten{display:flex;flex-direction:column;gap:6px;margin-bottom:8px}
.ctx-frame{position:relative;border:2px dashed var(--accent);border-radius:var(--radius-sm);padding:16px 12px 12px;background:var(--bg)}
.ctx-label{position:absolute;top:-9px;left:14px;background:var(--bg);padding:0 7px;font-size:.66rem;
  text-transform:uppercase;letter-spacing:.08em;color:var(--accent);font-weight:600}
#ctx-msgs{display:flex;flex-direction:column;gap:7px}
.ctx-msg{font-size:.86rem;line-height:1.45;padding:8px 12px;border-radius:12px;max-width:82%;animation:fade .3s ease}
.ctx-msg.you{background:var(--accent-weak);color:var(--ink);align-self:flex-end;margin-left:auto}
.ctx-msg.ai{background:var(--panel);color:var(--ink);align-self:flex-start}
.ctx-msg.faded{opacity:.45;filter:grayscale(1)}

/* ----------  Hallucination citation (lesson 14)  ---------- */
.cite{background:var(--panel);border:1px solid var(--line);border-left:3px solid var(--ink);
  border-radius:var(--radius-sm);padding:12px 14px;font-size:.9rem;line-height:1.55;color:var(--ink)}
.cite-verdict{margin-top:12px;background:#fef3f2;border:1px solid #fda29b;border-left:3px solid #d92d20;
  border-radius:var(--radius-sm);padding:12px 14px;font-size:.88rem;line-height:1.5;color:#912018}
.cite-verdict b{color:#b42318}

/* ----------  Mistakes  ---------- */
.mcard{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:22px}
.mcard h3{margin:0 0 8px}
.mcard .fix{margin-top:12px;font-size:.86rem;background:var(--bg-soft);border:1px solid var(--line);
  border-left:2px solid var(--accent);border-radius:var(--radius-sm);padding:11px 13px;color:var(--text)}
.mcard .fix b{color:var(--ink)}

/* ----------  Prompt before/after  ---------- */
.tabs{display:flex;gap:8px;margin-bottom:16px;flex-wrap:wrap}
.tab{cursor:pointer;padding:8px 16px;border-radius:999px;font-weight:600;font-size:.86rem;
  border:1px solid var(--line-strong);background:var(--bg);color:var(--muted)}
.tab.on{background:var(--ink);color:#fff;border-color:var(--ink)}
.ppanel{display:none}
.ppanel.on{display:block;animation:fade .3s ease}
.bubble{border-radius:var(--radius);padding:14px 16px;margin:8px 0;max-width:92%;font-size:.95rem;line-height:1.6}
.bubble.you{background:var(--accent-weak);margin-left:auto;color:var(--ink)}
.bubble.ai{background:var(--bg-soft);border:1px solid var(--line)}
.bubble .who{font-size:.7rem;font-weight:600;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);margin-bottom:4px}
.tips{display:grid;grid-template-columns:repeat(auto-fit,minmax(232px,1fr));gap:14px;margin-top:22px}
.tip{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.tip .n{font-weight:700;color:var(--accent);font-size:.95rem;font-variant-numeric:tabular-nums}
.tip h4{margin:8px 0 5px}
.tip p{margin:0;font-size:.88rem;color:var(--muted);line-height:1.55}

/* ----------  Agent loop (lesson 16)  ---------- */
.agent-loop{display:flex;flex-direction:column;gap:13px;max-height:360px;overflow:auto;padding:2px}
.ag-step{border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:var(--radius-sm);
  padding:10px 13px;background:var(--bg-soft);animation:fade .3s ease}
.ag-loopno{font-size:.65rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);font-weight:700;margin-bottom:6px}
.ag-row{display:flex;gap:9px;align-items:baseline;font-size:.9rem;line-height:1.5;margin-top:5px;color:var(--text)}
.ag-tag{flex:none;font-size:.63rem;text-transform:uppercase;letter-spacing:.04em;font-weight:700;
  padding:2px 8px;border-radius:999px;background:var(--panel);color:var(--muted)}
.ag-row.think .ag-tag{background:var(--accent-weak);color:var(--accent-ink)}
.ag-row.act .ag-tag.tool{background:#fff3e6;color:#9a5b00}
.ag-row.obs .ag-tag.res{background:#e9f7ee;color:#1f7a3d}
.ag-row.act code{font-family:var(--mono);font-size:.83rem;background:var(--panel);border:1px solid var(--line);
  border-radius:5px;padding:1px 6px;color:var(--ink);word-break:break-word}
.ag-done{border:1px solid var(--accent);background:var(--accent-weak);color:var(--accent-ink);
  border-radius:var(--radius-sm);padding:12px 14px;font-weight:600;animation:fade .3s ease}

/* ----------  Glossary  ---------- */
.gloss details{border:1px solid var(--line);border-radius:var(--radius-sm);margin-bottom:8px;background:var(--bg);overflow:hidden}
.gloss summary{cursor:pointer;padding:15px 18px;font-weight:600;color:var(--ink);list-style:none;display:flex;justify-content:space-between;align-items:center;gap:14px}
.gloss summary::-webkit-details-marker{display:none}
.gloss summary::after{content:"+";color:var(--muted);font-size:1.3rem;font-weight:400;line-height:1}
.gloss details[open] summary::after{content:"\2212"}
.gloss details[open] summary{border-bottom:1px solid var(--line)}
.gloss .body{padding:14px 18px 16px;color:var(--text);font-size:.93rem;line-height:1.6}

/* ----------  Recap  ---------- */
.recap{background:var(--ink);color:#fff;border-radius:16px;padding:34px}
.recap h2{color:#fff}
.recap ol{margin:16px 0 0;padding-left:0;list-style:none;counter-reset:r}
.recap li{margin-bottom:14px;font-size:1.02rem;line-height:1.55;padding-left:38px;position:relative;color:#e9eaf2}
.recap li::before{counter-increment:r;content:counter(r);position:absolute;left:0;top:1px;
  width:24px;height:24px;border-radius:50%;background:rgba(255,255,255,.12);color:#fff;
  display:grid;place-items:center;font-size:.8rem;font-weight:600}
.recap li b{color:#fff;font-weight:680}

/* ----------  Pager  ---------- */
.pager{max-width:var(--maxw);margin:32px auto 0;padding:26px 24px;display:flex;gap:12px;
  align-items:stretch;justify-content:space-between;border-top:1px solid var(--line);flex-wrap:wrap}
.pg{flex:1;min-width:150px;text-decoration:none;color:inherit;border:1px solid var(--line);
  border-radius:var(--radius);padding:14px 18px;transition:border-color .15s,box-shadow .15s,transform .1s;background:var(--bg)}
.pg:hover{border-color:var(--line-strong);box-shadow:var(--shadow-sm);transform:translateY(-2px);text-decoration:none}
.pg .dir{font-size:.72rem;font-weight:600;text-transform:uppercase;letter-spacing:.09em;color:var(--muted)}
.pg .ttl{font-weight:600;color:var(--ink);margin-top:2px}
.pg.next{text-align:right}
.pg.invisible{visibility:hidden}
footer.course{padding:22px 24px 70px;text-align:center;color:var(--muted);font-size:.82rem}
footer.course a{color:var(--muted)}

/* ----------  Reveal  ---------- */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease}
.reveal.in{opacity:1;transform:none}
@keyframes fade{from{opacity:0}to{opacity:1}}

@media(prefers-reduced-motion:reduce){
  .reveal{opacity:1;transform:none;transition:none}
  *{animation-duration:.001s!important;scroll-behavior:auto}
}

/* ----------  Train-once vs chat-time contrast (lesson 13)  ---------- */
.twophase{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:6px 0 4px}
@media(max-width:680px){.twophase{grid-template-columns:1fr}}
.tp{border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px 14px}
.tp-train{background:var(--bg-soft);border-color:var(--line-strong)}
.tp-chat{background:var(--accent-weak);border-color:#cdd0f7}
.tp-tag{font-size:.72rem;font-weight:700;letter-spacing:.04em;text-transform:uppercase;margin-bottom:5px;color:var(--muted)}
.tp-chat .tp-tag{color:var(--accent-ink)}
.tp-title{font-size:1.16rem;font-weight:680;color:var(--ink);margin-bottom:10px}
.tp-list{list-style:none;margin:0;padding:0}
.tp-list li{position:relative;padding-left:17px;margin-bottom:7px;font-size:.92rem;line-height:1.45;color:var(--text)}
.tp-list li::before{content:"";position:absolute;left:2px;top:.6em;width:5px;height:5px;border-radius:50%;background:var(--muted);opacity:.55}
.tp-chat .tp-list li::before{background:var(--accent);opacity:.7}
.tp-foot{margin-top:12px;padding-top:11px;border-top:1px solid var(--line);font-size:.9rem;color:var(--ink);font-weight:600}
.tp-train .tp-foot{color:var(--muted)}

/* ----------  "Why counting is hard" tokens (lesson 14)  ---------- */
#count-in{max-width:300px}
.count-q{margin-top:14px;font-size:.95rem;color:var(--text)}
.count-q b{color:var(--ink)}

/* ----------  "You be the human rater" / RLHF (lesson 12)  ---------- */
.rate-q{font-weight:600;color:var(--ink);margin:16px 0 12px}
.rate-pair{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media(max-width:680px){.rate-pair{grid-template-columns:1fr}}
.rate-ans{text-align:left;cursor:pointer;font-family:var(--font);font-size:.92rem;line-height:1.5;color:var(--text);
  background:var(--bg);border:1px solid var(--line-strong);border-radius:var(--radius);padding:14px 16px;
  transition:border-color .15s,box-shadow .15s,transform .1s}
.rate-ans:hover{border-color:var(--accent);box-shadow:var(--shadow-sm);transform:translateY(-1px)}
.rate-ans:disabled{cursor:default;transform:none;box-shadow:none}
.rate-ans .lbl{display:block;font-size:.72rem;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--muted);margin-bottom:6px}
.rate-ans .why{display:none;margin-top:9px;font-size:.82rem;font-style:italic;color:var(--muted)}
.rate-ans.show-why .why{display:block}
.rate-ans.good{border-color:#1f7a3d;background:#e9f7ee}
.rate-ans.good .lbl{color:#1f7a3d}
.rate-ans.bad{border-color:var(--line);background:var(--bg-soft);opacity:.66}
.rate-profile{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin-top:16px}
.rate-profile .plab{font-size:.82rem;color:var(--muted);margin-right:2px}
.rate-chip{font-size:.82rem;font-weight:600;padding:5px 12px;border-radius:999px;border:1px solid var(--line-strong);
  color:var(--muted);background:var(--bg);transition:background .25s,color .25s,border-color .25s}
.rate-chip.on{border-color:var(--accent);background:var(--accent-weak);color:var(--accent-ink)}
.rate-end{background:var(--accent-weak);border:1px solid #cdd0f7;border-radius:var(--radius);padding:16px 18px;color:var(--ink);line-height:1.6}

/* ----------  Multimodal "same engine, any input" (going further)  ---------- */
.mm-flow{display:flex;align-items:center;gap:10px;margin:10px 0 4px}
@media(max-width:680px){.mm-flow{flex-direction:column;align-items:stretch}}
.mm-col{flex:1;min-width:0;text-align:center}
.mm-col-lab{font-size:.78rem;color:var(--muted);margin-bottom:8px}
.mm-col-lab b{color:var(--ink)}
.mm-sub{font-size:.72rem;color:var(--muted);margin-top:8px;line-height:1.4}
.mm-arrow{color:var(--line-strong);font-size:1.3rem;flex:0 0 auto}
@media(max-width:680px){.mm-arrow{transform:rotate(90deg)}}
.mm-pieces{display:flex;flex-wrap:wrap;gap:5px;justify-content:center;align-items:center;min-height:88px;
  padding:12px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--bg-soft)}
.mm-piece{animation:fade .25s ease}
.mm-tok{padding:5px 9px;border-radius:6px;font-size:.86rem;font-weight:500;background:var(--panel);color:var(--ink);border:1px solid var(--line)}
.mm-pieces.mode-image{display:grid;grid-template-columns:repeat(4,1fr);gap:3px;max-width:140px;margin:0 auto}
.mm-patch{display:block;width:100%;aspect-ratio:1/1;border-radius:3px}
.mm-pieces.mode-sound{align-items:flex-end;gap:2px}
.mm-bar{display:block;width:5px;background:var(--accent);border-radius:2px;opacity:.8}
.mm-vecs{display:flex;flex-direction:column;gap:5px;align-items:center;justify-content:center;min-height:88px;
  padding:12px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--bg-soft)}
.mm-vrow{display:flex;gap:3px}
.mm-vrow i{width:11px;height:8px;border-radius:2px;background:var(--accent);opacity:.55}
.mm-vrow i:nth-child(2n){opacity:.32}
.mm-vrow i:nth-child(3n){opacity:.72}
.mm-model{display:flex;align-items:center;justify-content:center;min-height:88px;padding:12px;font-weight:600;
  color:var(--accent-ink);background:var(--accent-weak);border:1px solid #cdd0f7;border-radius:var(--radius-sm);line-height:1.3}

/* ----------  RAG "answer from your documents" (going further)  ---------- */
.rag-q{margin:4px 0 14px;font-weight:600;color:var(--ink)}
.rag-pin{display:inline-block;font-size:.68rem;font-weight:700;text-transform:uppercase;letter-spacing:.04em;color:var(--muted);
  background:var(--panel);border:1px solid var(--line);border-radius:5px;padding:2px 7px;margin-right:8px;vertical-align:middle}
.rag-pin.q{color:var(--accent-ink);background:var(--accent-weak);border-color:#cdd0f7}
.rag-stage{min-height:150px}
.rag-lab2{font-size:.78rem;color:var(--muted);margin-bottom:10px}
.rag-lib{display:grid;grid-template-columns:1fr 1fr;gap:10px}
@media(max-width:560px){.rag-lib{grid-template-columns:1fr}}
.rag-doc{border:1px solid var(--line);border-radius:var(--radius-sm);padding:12px 14px;background:var(--bg);
  transition:opacity .25s,border-color .25s,background .25s}
.rag-doc-t{font-weight:600;color:var(--ink);font-size:.92rem;margin-bottom:4px}
.rag-doc-b{font-size:.84rem;color:var(--muted);line-height:1.45}
.rag-doc.hit{border-color:var(--accent);background:var(--accent-weak)}
.rag-doc.hit .rag-doc-b{color:var(--text)}
.rag-doc.dim{opacity:.4}
.rag-prompt{border:1px solid var(--line-strong);border-radius:var(--radius-sm);padding:14px;background:var(--bg-soft)}
.rag-inject{background:var(--accent-weak);border:1px solid #cdd0f7;border-radius:6px;padding:10px 12px;font-size:.9rem;color:var(--ink);margin-bottom:10px}
.rag-userq{font-size:.9rem;color:var(--ink);padding:0 2px}
.rag-answer{border:1px solid #bfe3cb;background:#e9f7ee;border-radius:var(--radius-sm);padding:14px 16px}
.rag-answer p{margin:0;color:var(--ink)}
.rag-cite{display:inline-block;font-size:.8rem;color:#1f7a3d;font-weight:600;margin-left:4px}