/* Guided workbook: one idea, one visual, one task. */
:root,:root[data-theme="light"]{--bg:#f4f6fa;--surface:#fff;--surface-2:#eef2f8;--ink:#182641;--muted:#53617a;--line:#dce3ee;--accent:#3158d5;--accent-ink:#264ac1;--accent-soft:#eaf0ff;--purple:#7153cc;--good:#087d70;--on-accent:#fff;--shadow:none}
:root[data-theme="dark"]{--bg:#0e1524;--surface:#172137;--surface-2:#202e46;--ink:#edf2ff;--muted:#adbbd3;--line:#34435d;--accent:#98b2ff;--accent-ink:#b5c8ff;--accent-soft:#263958;--purple:#c0a8ff;--good:#5ed4c1;--on-accent:#0e1524;--shadow:none}
html{scroll-behavior:auto}body{font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;font-size:16px;line-height:1.6}button,input,textarea{font:inherit}button,a,input,summary,textarea{touch-action:manipulation}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible,textarea:focus-visible,[tabindex]:focus-visible{outline:3px solid var(--accent);outline-offset:4px}
#top-nav{height:72px;padding:0 28px;background:var(--surface);backdrop-filter:none}.nav-container{height:100%;max-width:none}.nav-brand{font-size:16px;gap:12px}.nav-brand .badge{font-size:14px;padding:7px 10px;background:var(--ink)}.header-course{font-size:12px;letter-spacing:.12em;color:var(--muted)}.theme-switch{background:var(--surface-2);padding:4px;border-radius:8px}.theme-opt{font-size:14px;min-height:34px}
.lesson-nav{position:fixed;left:0;top:72px;bottom:0;width:256px;padding:26px 16px;overflow:auto;border-right:1px solid var(--line);background:var(--surface);display:flex;flex-direction:column;gap:4px}.nav-pill{display:flex;align-items:center;gap:10px;padding:9px 12px;white-space:normal;font-size:14px;min-height:42px;border-radius:7px}.nav-pill.active{background:var(--accent-soft);color:var(--accent-ink);font-weight:650}.main-wrapper{max-width:1180px;margin:0 auto 0 256px;padding:38px 48px 64px}.lesson{margin:0;padding:0;border:0;background:transparent;box-shadow:none;scroll-margin-top:95px}.lesson>h1,.lesson-heading h1{font-size:clamp(28px,3vw,42px);line-height:1.15;letter-spacing:-.035em;margin:10px 0 16px}.lesson-heading{margin-bottom:24px}.lesson-heading p{font-size:18px;max-width:64ch;margin:0;color:var(--muted)}.eyebrow{font-size:12px;font-weight:700;letter-spacing:.13em;text-transform:uppercase;color:var(--accent-ink)}.panel,.fig,.remember,.note,.answer,.deeper{box-shadow:none;border-radius:12px}.panel{padding:22px;background:var(--surface);border:1px solid var(--line);margin:20px 0}.plbl{font-size:15px;letter-spacing:0;text-transform:none;gap:12px;flex-wrap:wrap}.btn{font-size:14px;min-height:38px;padding:7px 14px;border-radius:7px}.btn.on{background:var(--accent-soft);color:var(--accent-ink);border-color:var(--accent)}.pill{font-size:12px}.cap,.small{font-size:14px;line-height:1.6}.fig{background:var(--surface);overflow:hidden}.fig img{max-height:500px;object-fit:contain;margin:auto}.fig .cap{padding:14px 18px}.statrow{gap:12px}.stat{background:transparent;border:0;padding:10px 14px;text-align:left}.stat .v{font-size:26px}.stat .l{font-size:13px}.slider-row label{font-size:14px}.remember,.note{padding:18px 22px}.duo{gap:20px}.qhead h2{font-size:32px}.flow{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-pager{display:flex;justify-content:space-between;gap:16px;margin-top:32px;padding:24px 0;border-top:1px solid var(--line)}.primary{background:var(--accent)!important;color:var(--on-accent)!important;border-color:var(--accent)!important}.chapter-label{margin:22px 12px 5px;font-size:12px;letter-spacing:.1em;text-transform:uppercase;font-weight:700;color:var(--muted)}.nav-number{font-size:12px;font-variant-numeric:tabular-nums;opacity:.65;min-width:20px}.nav-title{flex:1}.nav-check{font-size:13px;color:var(--good)}.course-progress{padding:0 12px 14px;border-bottom:1px solid var(--line)}.course-progress p{font-size:14px;margin:6px 0}.progress-track{height:4px;background:var(--line);border-radius:8px;overflow:hidden}.progress-track span{display:block;height:100%;background:var(--accent);transition:width .3s}.top-actions{display:flex;gap:12px;align-items:center}.menu-toggle{display:none}.lesson-meta{display:flex;align-items:center;justify-content:space-between;gap:10px}.lesson-meta .pill{background:var(--surface);border:1px solid var(--line)}.takeaway{border-left:3px solid var(--accent);padding:3px 0 3px 18px;margin:24px 0;max-width:75ch}.takeaway p{margin:0}.task-card{padding:22px;border:1px solid var(--line);background:var(--surface);border-radius:12px;margin-top:24px}.task-card h2{font-size:19px;margin:4px 0 10px}.task-card p{margin:8px 0}.task-card textarea{display:block;width:100%;min-height:88px;resize:vertical;padding:12px;background:var(--bg);color:var(--ink);border:1px solid var(--line);border-radius:7px;font-size:16px;margin:12px 0}.answer{margin:12px 0 0}.answer-toggle{font-size:15px;padding:15px 18px;width:100%;text-align:left;min-height:48px}.answer-body{font-size:16px}.answer-body p:last-child{margin-bottom:0}.deeper{background:var(--surface);border:1px solid var(--line);margin:14px 0}.deeper summary{font-size:15px;padding:16px 20px;cursor:pointer}.detail-body{padding:0 20px 20px}.detail-body .deeper{background:var(--bg)}pre{font-size:14px;line-height:1.65;border-radius:8px;max-height:480px;overflow:auto;padding:18px}code{font-size:.88em}.code-tools{display:flex;justify-content:space-between;align-items:center;font-size:12px;color:var(--muted);margin-top:16px}.code-tools button{font-size:13px;padding:4px 10px;min-height:32px}.visual-label{font-size:12px;color:var(--muted);display:flex;justify-content:space-between;gap:12px;margin-bottom:14px}.stepper{padding:22px;background:var(--surface);border:1px solid var(--line);border-radius:12px;margin:20px 0}.stepper-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.stepper-top strong{font-size:15px}.process-track{display:flex;gap:8px;align-items:stretch}.process-node{position:relative;flex:1;min-width:0;min-height:78px;padding:10px 8px;border:1px solid var(--line);border-radius:8px;background:var(--bg);color:var(--muted);text-align:left;transition:background .25s,border-color .25s,transform .25s;font-size:14px}.process-node b{display:block;font-size:12px;margin-bottom:7px;font-weight:500}.process-node.active{border-color:var(--accent);background:var(--accent-soft);color:var(--accent-ink);transform:translateY(-3px)}.process-node.active:after{content:"";height:3px;background:var(--accent);position:absolute;left:10px;right:10px;bottom:0}.process-caption{min-height:76px;margin-top:20px;border-top:1px solid var(--line);padding-top:16px}.process-caption h3{font-size:17px;margin:0 0 4px}.process-caption p{margin:0;color:var(--muted);font-size:16px}.process-slide[hidden]{display:none}.mini-metrics{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:20px 0}.mini-metric{border-bottom:1px solid var(--line);padding:16px 4px}.mini-metric b{display:block;font-size:27px;font-weight:600;letter-spacing:-.03em}.mini-metric span{font-size:14px;color:var(--muted)}.split-view{display:grid;grid-template-columns:1.2fr 1fr;gap:22px;align-items:start}.split-view>*{min-width:0}.image-stage{background:#101723;padding:24px;border-radius:10px;text-align:center}.image-stage img{image-rendering:pixelated;margin:auto;max-height:260px}.image-stage p{color:#c6d5ef;font-size:14px}.visual-compare{display:grid;grid-template-columns:1fr 1fr;gap:16px}.visual-compare .fig{margin:0}.chapter-footer{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.chapter-footer label{font-size:14px;margin-right:12px;cursor:pointer}.chapter-footer input{margin-right:8px;accent-color:var(--accent);width:17px;height:17px}.lesson-count{font-size:13px;color:var(--muted)}.app-notice{font-size:13px;color:var(--muted);margin-top:12px}.hotspot-card{padding:20px}.hotspot-card p{font-size:16px}.rep-map{background:#fff;border-radius:8px}.score-bars{display:grid;grid-template-columns:1fr 1fr;gap:6px 24px}.score-row{font-size:13px}.arch-flow{overflow-x:auto}.arch-box{min-width:95px}.source-output img{max-height:450px;object-fit:contain}.source-output pre{max-height:200px}.source-output{margin:16px 0}.all-lessons .lesson{display:block!important;margin-bottom:80px}.all-lessons .lesson-pager{display:none}.all-lessons .lesson[hidden]{display:block!important}.live-status{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}.mobile-shade{display:none}.slide-choice{display:flex;gap:8px;flex-wrap:wrap}.slide-choice button{flex:1}.source-map{font-size:14px}.learning-hint{font-size:14px;margin:14px 0;color:var(--muted)}
@media(min-width:1600px){.main-wrapper{margin-left:calc(256px + (100vw - 1600px)/2)}}
@media(max-width:1100px){.lesson-nav{width:220px}.main-wrapper{margin-left:220px;padding:30px 28px}.header-course{display:none}.duo,.duo.w23,.duo.w32{grid-template-columns:1fr}.split-view{grid-template-columns:1fr}.process-track{gap:5px}.process-node{font-size:13px}.score-bars{grid-template-columns:1fr}}
@media(max-width:760px){#top-nav{height:64px;padding:0 16px}.nav-brand{font-size:14px}.nav-brand .badge{font-size:12px}.nav-brand>span:last-child{display:none}.menu-toggle{display:block}.lesson-nav{display:none;top:64px;width:min(320px,86vw);z-index:999;box-shadow:20px 0 60px #0003}.nav-open .lesson-nav{display:flex}.main-wrapper{margin:0;padding:25px 18px 36px}.theme-opt{padding:5px 8px;font-size:13px}.top-actions{gap:6px}.top-actions>.btn{font-size:13px;padding:6px 10px}.lesson-heading p{font-size:16px}.lesson-heading h1{font-size:30px}.panel,.stepper,.task-card{padding:16px}.process-track{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.process-node{min-height:65px;font-size:14px}.process-caption{min-height:100px}.visual-compare{grid-template-columns:1fr}.mini-metric b{font-size:23px}.mini-metric span{font-size:13px}.flow{grid-template-columns:1fr}.lesson-pager{flex-wrap:wrap}.chapter-footer{width:100%;justify-content:space-between}.statrow{flex-wrap:wrap}.slider-row{flex-wrap:wrap}.slider-row input{min-width:100px}.katex-display{font-size:.9em}.source-map{overflow:auto}.nav-open .mobile-shade{display:block;position:fixed;inset:64px 0 0;background:#0006;z-index:998;border:0;width:100%}.fig img{max-height:360px}.btnrow{gap:7px}.lesson-meta{align-items:flex-start}.detail-body{padding:0 14px 14px}}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
@media print{#top-nav,.lesson-nav,.lesson-pager,.top-actions,.mobile-shade{display:none!important}.main-wrapper{margin:0;padding:0}.lesson,.lesson[hidden]{display:block!important;break-before:page}.lesson:first-child{break-before:auto}.answer-body,.process-slide[hidden]{display:block!important}.answer-toggle{display:none}.panel,.task-card,.stepper{break-inside:avoid}body{background:#fff;color:#111}.task-card textarea{min-height:65px}details:not([open])>*{display:block!important}}
.ae-intro-stage{display:flex;align-items:center;justify-content:space-around;gap:16px;padding:36px 24px;background:var(--surface);border:1px solid var(--line);border-radius:12px;margin:24px 0 0;min-height:225px}.ae-picture{width:145px;flex-shrink:0;text-align:center}.ae-picture img{width:108px;height:108px;object-fit:contain;image-rendering:pixelated;margin:auto;border-radius:7px;background:#090d16}.ae-picture span{display:block;font-size:14px;margin-top:12px}.ae-link{flex:1;max-width:150px;color:var(--accent-ink);text-align:center;font-size:14px}.ae-link i{display:block;height:2px;background:var(--line);margin-top:12px;position:relative}.ae-link i:after{content:"";position:absolute;right:0;top:-4px;border-left:8px solid var(--accent);border-top:5px solid transparent;border-bottom:5px solid transparent}.latent-beads{display:grid;grid-template-columns:repeat(4,10px);gap:5px}.latent-beads i{height:10px;background:var(--accent);opacity:.6;border-radius:2px}.latent-beads i:nth-child(3n){opacity:.2}.latent-beads i:nth-child(5n){opacity:1}.lesson.process-playing .ae-link i{background:linear-gradient(90deg,var(--line),var(--accent),var(--line));background-size:200%;animation:flow-signal 1.5s linear infinite}.lesson.process-playing .latent-beads i{animation:code-pulse 1.5s ease-in-out infinite}.lesson.process-playing .latent-beads i:nth-child(2n){animation-delay:.3s}@keyframes flow-signal{to{background-position:-200% 0}}@keyframes code-pulse{50%{opacity:.2}}.scale-swatch{height:26px;border-radius:5px;border:1px solid var(--line);margin-top:22px}.loss-cards{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:22px 0}.loss-cards>div{background:var(--surface);border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:8px;padding:20px}.loss-cards>div:last-child{border-top-color:var(--purple)}.loss-cards h3{font-size:19px;margin:9px 0}.loss-cards p{margin:0;font-size:16px}.nn-results{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin:24px 0 0}.nn-result{text-align:center;animation:reveal-result .35s ease-out both}.nn-result:nth-child(2){animation-delay:.08s}.nn-result:nth-child(3){animation-delay:.16s}.nn-result:nth-child(4){animation-delay:.24s}.nn-result canvas{display:block;width:100%;max-width:150px;height:auto;aspect-ratio:1;image-rendering:pixelated;margin:8px auto;border-radius:7px;border:3px solid var(--line)}.nn-result:first-child canvas{border-color:var(--accent)}.nn-result b{font-size:14px}.nn-result p{font-size:12px;line-height:1.6;margin:6px 0;color:var(--muted)}@keyframes reveal-result{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}.walk-stage{display:flex;justify-content:center;gap:48px;padding:24px}.walk-stage>div{width:180px;text-align:center}.walk-stage canvas{width:100%;image-rendering:pixelated;border-radius:8px;background:#111}.walk-stage p{font-size:14px;margin:10px 0}.walk-line{margin:20px 5% 10px;height:2px;background:var(--line);position:relative;display:flex;justify-content:space-between}.walk-line span{position:relative;top:10px;font-size:14px}.walk-line i{position:absolute;width:12px;height:12px;border-radius:50%;background:var(--accent);top:-5px;left:0}.quality-stage{display:grid;grid-template-columns:repeat(8,1fr);gap:8px;padding:24px 0}.quality-stage img{width:100%;aspect-ratio:1;object-fit:cover;image-rendering:pixelated;border-radius:5px;background:#000}.quality-stage canvas{width:100%;aspect-ratio:1;border-radius:5px}.quality-stage img.soft{filter:blur(1px)}#loss-chart{width:100%;height:auto;display:block;overflow:visible}#hourglass{min-width:660px;width:100%}#hourglass-lab{overflow-x:auto}.source-markdown{white-space:pre-wrap;overflow-wrap:anywhere;max-height:320px}.source-cell summary{overflow-wrap:anywhere}#quality-caption{min-height:52px}.bar-track:after{content:"";position:absolute;left:50%;top:0;bottom:0;width:1px;background:var(--muted)}.score-row .bar-track{position:relative}.score-row .bar-fill{position:absolute;top:0;height:100%;transition:width .3s,left .3s}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@media(max-width:760px){.ae-intro-stage{gap:8px;padding:24px 12px;min-height:180px}.ae-picture{width:80px}.ae-picture img{width:74px;height:74px}.ae-picture span{font-size:12px}.ae-link{font-size:12px}.latent-beads{grid-template-columns:repeat(4,5px);gap:3px}.latent-beads i{height:5px}.loss-cards{grid-template-columns:1fr}.nn-results{grid-template-columns:repeat(2,1fr);gap:16px}.walk-stage{gap:20px;padding:15px 0}.quality-stage{grid-template-columns:repeat(4,1fr)}.ae-link i{min-width:14px}.source-cell summary{font-size:14px}}
@media print{.answer-body[hidden]{display:block!important}.process-slide[hidden]{display:block!important;margin-top:14px}.process-node{transform:none!important}.source-cell:not([open]) .detail-body{display:none!important}.lesson-heading{break-after:avoid}}
/* Make the learning purpose visible before the activity. */
.lesson-intent{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-top:20px;padding-top:18px;border-top:1px solid var(--line)}
.lesson-heading .lesson-intent p{font-size:15px;line-height:1.65;margin:0}
.lesson-intent strong{display:block;color:var(--ink);font-size:13px;text-transform:uppercase;letter-spacing:.06em;margin-bottom:5px}
.metric-heading h2,.birthday-bridge h2{font-size:25px;line-height:1.25;letter-spacing:-.025em;margin:8px 0 12px}
.metric-heading>p{margin:0 0 24px;max-width:68ch}.metric-explainer{padding:26px}.birthday-layout{display:grid;grid-template-columns:1.25fr 1fr;gap:28px;align-items:center;margin-top:18px}.birthday-layout>div{min-width:0}
#birthday-pairs{display:block;width:100%;height:auto}.birthday-results>strong{font-size:54px;line-height:1.15;font-variant-numeric:tabular-nums;letter-spacing:-.045em;display:block;margin-top:8px;color:var(--accent-ink)}.birthday-results>span{display:block}.birthday-results>p{font-size:15px;line-height:1.65;min-height:74px}.probability-row{display:grid;grid-template-columns:1fr auto;gap:6px;margin-top:22px;font-size:14px}.probability-row>div{grid-column:1/-1;height:9px;background:var(--surface-2);border-radius:8px;overflow:hidden}.probability-row i{display:block;height:100%;background:var(--accent);border-radius:8px;transition:width .35s}.probability-row:first-of-type i{background:var(--purple)}.reason-strip{padding:18px 20px;border-left:3px solid var(--accent);background:var(--accent-soft);border-radius:0 8px 8px 0;margin:22px 0}.reason-strip strong{font-size:16px}.reason-strip p{font-size:15px;line-height:1.65;margin:5px 0 0}.probability-chain{display:flex;gap:9px;flex-wrap:wrap;align-items:center;padding:18px 0}.probability-chain span{background:var(--surface-2);padding:8px 12px;border-radius:6px;font-size:15px}.birthday-bridge{margin:32px 0 22px}.analogy-grid{display:grid;grid-template-columns:1fr auto 1fr;gap:22px;align-items:center;margin:18px 0}.analogy-grid>div:not(.analogy-arrow){padding:20px;background:var(--surface);border:1px solid var(--line);border-radius:9px}.analogy-grid span{display:block;font-size:13px;color:var(--muted)}.analogy-grid strong{display:block;font-size:20px;margin-top:4px}.analogy-grid p{margin:8px 0 0;font-size:15px}.analogy-arrow{font-size:28px;color:var(--accent)}.metric-presets{display:flex;gap:8px;flex-wrap:wrap;margin:20px 0}.metric-presets .btn{flex:1}.is-controls{padding:6px 0 14px}.is-controls .slider-row label{min-width:230px}.is-visual-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:18px;margin:20px 0}.is-focus-panel{padding:18px;border:2px solid var(--line);border-radius:10px;min-width:0;transition:border-color .3s,background .3s}.is-focus-panel h3{font-size:17px;margin:0 0 8px}.is-focus-panel .small{margin:0 0 16px}.is-visual-grid[data-is-stage="0"] .is-individual,.is-visual-grid[data-is-stage="1"] .is-aggregate,.is-visual-grid[data-is-stage="2"] .is-focus-panel{border-color:var(--accent)}.is-key,.is-image-row{display:grid;grid-template-columns:52px repeat(3,minmax(0,1fr));gap:9px;align-items:center}.is-key{font-size:13px;text-align:center;color:var(--muted);margin-bottom:8px}.is-image-row{margin:10px 0}.is-image-row img{width:44px;height:44px;image-rendering:pixelated;border-radius:5px;background:#000}.is-probability{position:relative;height:32px;background:var(--surface-2);border-radius:4px;overflow:hidden;text-align:center}.is-probability i{position:absolute;inset:0 auto 0 0;background:var(--accent-soft);border-bottom:3px solid var(--accent);transition:width .35s}.is-probability[data-class="1"] i{background:var(--good-soft);border-color:var(--good)}.is-probability[data-class="2"] i{background:var(--purple-soft);border-color:var(--purple)}.is-probability span{position:relative;z-index:1;font-size:13px;line-height:32px;color:var(--ink);font-variant-numeric:tabular-nums}.is-average-row{display:grid;grid-template-columns:45px 1fr;gap:10px;align-items:center;margin:12px 0;font-size:14px}.is-score-box{display:flex;flex-direction:column;text-align:center;border-top:1px solid var(--line);padding-top:20px;margin-top:20px}.is-score-box>strong{font-size:52px;line-height:1.2;letter-spacing:-.045em;color:var(--accent-ink);font-variant-numeric:tabular-nums}.is-score-box>span{font-size:13px;color:var(--muted)}.is-entropy{margin-top:22px;border-top:1px solid var(--line);padding-top:12px}.is-entropy p{display:flex;justify-content:space-between;gap:12px;font-size:13px;margin:8px 0}.metric-explanation{padding:16px 0;border-bottom:1px solid var(--line);min-height:90px;font-size:16px}.repeat-control{display:flex;align-items:center;gap:12px;font-size:16px;padding:12px 0}.repeat-control input{width:20px;height:20px;accent-color:var(--accent)}
@media(max-width:1050px){.birthday-layout,.is-visual-grid{grid-template-columns:1fr}.birthday-layout>div:first-child{max-width:500px;margin:auto}.birthday-results{display:grid;grid-template-columns:1fr 1fr;gap:8px 22px}.birthday-results>.eyebrow,.birthday-results>p{grid-column:1/-1}.birthday-results>strong{font-size:40px}.birthday-results>span:not(.eyebrow){align-self:center}.is-individual{max-width:none}.is-controls .slider-row{flex-wrap:wrap}}
@media(max-width:760px){.lesson-intent{grid-template-columns:1fr;gap:12px;margin-top:14px}.metric-explainer{padding:16px}.metric-heading h2,.birthday-bridge h2{font-size:23px}.metric-presets{flex-direction:column}.analogy-grid{grid-template-columns:1fr;gap:12px}.analogy-arrow{transform:rotate(90deg);text-align:center}.is-focus-panel{padding:14px}.is-key,.is-image-row{grid-template-columns:44px repeat(3,minmax(0,1fr));gap:5px}.is-controls .slider-row label{min-width:0;width:100%}.probability-row{font-size:13px}.birthday-results{gap:8px 12px}.is-entropy p{font-size:13px}.metric-explanation{min-height:110px}}
@media(prefers-reduced-motion:reduce){.metric-explainer *{transition:none!important;animation:none!important}}
