@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500&display=swap');

:root{
 --bg:#FCFDFE;--surface:#FFFFFF;--fg:#0F141C;--muted:#586273;--accent:#1A5DB4;--accent-soft:#EDF4FB;--accent-border:rgba(26,93,180,.22);
 --line:rgba(20,20,20,.10);--line-strong:rgba(20,20,20,.16);--ok:#1E7F4F;--ok-soft:#E8F5EE;--warn:#B4541A;
 --font:'IBM Plex Sans',system-ui,-apple-system,'Segoe UI',sans-serif;--mono:'IBM Plex Mono',ui-monospace,Consolas,monospace;
 --radius:9px;--radius-small:8px;--shadow:0 22px 50px -30px rgba(15,30,60,.5);
}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{background:var(--bg);color:var(--fg);font-family:var(--font);font-size:16px;line-height:1.58;-webkit-font-smoothing:antialiased;display:grid;grid-template-rows:auto auto minmax(0,1fr) auto;height:100vh;min-height:100vh}
a{color:var(--accent)}
button,select,input,textarea{font:inherit;color:inherit}
button{cursor:pointer;background:var(--surface);border:1px solid var(--line-strong);border-radius:var(--radius-small);padding:5px 11px;font-size:14px;font-weight:500;line-height:1.3;transition:border-color .15s,background .15s}
button:hover{border-color:var(--accent);color:var(--accent)}
button:focus-visible,select:focus-visible,input:focus-visible,textarea:focus-visible,a:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
button[disabled]{opacity:.4;cursor:default}
button[disabled]:hover{border-color:var(--line-strong);color:inherit}
select,input:not([type=range]):not([type=checkbox]):not([type=radio]),textarea{background:var(--surface);border:1px solid var(--line-strong);border-radius:var(--radius-small);padding:5px 8px;font-size:inherit;max-width:100%}
textarea{width:100%;resize:vertical}
input[type=range]{accent-color:var(--accent);width:100%}
input[type=checkbox],input[type=radio]{accent-color:var(--accent)}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:8px;top:-40px;background:var(--accent);color:#fff;padding:6px 10px;border-radius:var(--radius-small);z-index:20}
.skip:focus{top:8px}

/* header */
.course-header{position:relative;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:18px;padding:0 22px;height:52px;border-bottom:1px solid var(--line);background:var(--surface);z-index:5}
.course-mark{justify-self:start;font-weight:700;font-size:14px;letter-spacing:.02em;text-decoration:none;color:var(--fg);white-space:nowrap}
.course-mark span{color:var(--muted);font-weight:500;margin-left:4px}
#chapter-nav{display:flex;gap:2px;justify-self:center;max-width:100%;min-width:0;overflow-x:auto;scrollbar-width:none;height:100%}
#chapter-nav::-webkit-scrollbar{display:none}
#chapter-nav a{display:flex;align-items:center;gap:6px;padding:0 9px;height:100%;font-size:12.5px;text-decoration:none;color:var(--muted);border-bottom:2px solid transparent;white-space:nowrap}
#chapter-nav a .num{font-size:11.5px;font-weight:600;opacity:.75}
#chapter-nav a:not(.active) .name{display:none}
#chapter-nav a:hover{color:var(--fg)}
#chapter-nav a.active{color:var(--accent);border-bottom-color:var(--accent);font-weight:600}
.skyline{height:30px;width:auto;opacity:.32;pointer-events:none;flex:0 0 auto;align-self:flex-end;margin:0 10px -1px 0}
.header-actions{display:flex;align-items:center;gap:6px;height:100%;justify-self:end}
.icon-button{width:32px;height:30px;padding:0;display:inline-flex;align-items:center;justify-content:center}
.icon-button svg{width:18px;height:18px;stroke:currentColor;fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
#present .icon-exit{display:none}
#present.is-fullscreen .icon-enter{display:none}
#present.is-fullscreen .icon-exit{display:block}
.language-control select{padding:4px 22px 4px 8px;font-size:12.5px;font-weight:600;letter-spacing:.04em}
.overall-track{height:3px;background:var(--line)}
#overall-progress{height:100%;width:0;background:var(--accent);transition:width .35s ease}

/* slide */
main#slide{display:flex;flex-direction:column;padding:34px clamp(22px,5vw,72px) 30px;max-width:1240px;width:100%;margin:0 auto;outline:none;overflow-y:auto;min-height:0}
.slide{display:flex;flex-direction:column;gap:14px;flex:1}
.slide h1{font-weight:700;font-size:clamp(26px,3.2vw,40px);line-height:1.08;letter-spacing:-.02em;margin:0}
.slide .lead{font-size:clamp(17px,1.5vw,20px);line-height:1.4;color:var(--muted);margin:0}
.slide .lead a{color:inherit;text-decoration:underline;text-decoration-color:var(--accent-border);text-underline-offset:3px}
.slide .lead a:hover{color:var(--accent)}
.slide-body{display:grid;grid-template-columns:1fr;gap:26px;align-items:start;margin-top:8px}
.slide-body.with-figure{grid-template-columns:minmax(0,1fr) minmax(0,1.3fr)}
.slide-body.with-figure.wide-text{grid-template-columns:minmax(0,7fr) minmax(0,3fr)}
.slide-body.with-figure.wide-text .points{max-width:none}
.slide-body.with-figure.half{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
.slide-body.with-figure.figure-only{grid-template-columns:1fr;justify-items:center}
.slide-body.with-figure.figure-only .figure-wrap{width:100%;max-width:900px}
/* stacked: the figure spans the full width, the bullet points follow underneath */
.slide-body.with-figure.stacked{grid-template-columns:1fr}
.slide-body.stacked .figure-wrap svg{max-height:50vh;width:100%}
.slide-body.stacked .figure-wrap.image img{width:100%;max-height:56vh;object-fit:contain}
.slide-body.stacked .points{max-width:none}
.slide-body.stacked .figure-wrap.image:only-child{width:85%;justify-self:center}
.slide-body.stacked .figure-wrap.image:only-child img{max-height:56vh}
.slide-body.lab-split{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
.slide-body.lab-split .lab{margin-top:0;min-width:0}
.points li.sub{padding-left:0;font-weight:600;color:var(--accent);margin-top:6px}
.points li.sub::before{display:none}
.math .katex{font-size:1.06em}
.slide-body.with-image{grid-template-columns:minmax(0,1.1fr) minmax(0,1fr)}
.slide-body.with-image .figure-wrap.image img{max-height:52vh;width:auto;max-width:100%;margin:0 auto}
.slide-body.with-images{grid-template-columns:minmax(0,1fr) minmax(0,1.3fr)}
.image-strip{display:grid;gap:14px;grid-template-columns:repeat(2,minmax(0,1fr))}
.image-strip.count-1{grid-template-columns:1fr}
.slide-body.with-images .image-strip:only-child{grid-column:1/-1}
.image-strip .figure-wrap.image img{aspect-ratio:4/3;object-fit:contain;background:#fff}
.image-strip .figure-wrap figcaption{font-size:clamp(16px,1.3vw,18.5px);color:var(--fg);line-height:1.45}
.image-strip figcaption .credit{display:block;color:var(--muted);font-size:13px;margin-top:4px}
.image-strip figcaption .credit a{color:inherit}
.figure-wrap.figure-second{margin-top:6px}
.figure-wrap.figure-second svg{max-height:300px;width:auto;margin:0 auto}
.slide.centered{justify-content:center;align-items:center;text-align:center}
.slide.centered h1,.slide.centered .lead{max-width:none}
.slide.centered .points{max-width:none;align-items:center;gap:16px;margin-top:8px}
.slide.centered .points li{padding:14px 22px;font-size:clamp(18px,1.7vw,23px);background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);max-width:34ch}
.slide.centered .points li::before{display:none}
.slide.centered .question{align-self:stretch;text-align:left}
.slide.centered .slide-sources{align-self:stretch;text-align:left}
.contents-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));grid-auto-flow:column;grid-template-rows:repeat(4,auto);gap:12px 32px;margin-top:10px}
.contents-item{display:grid;grid-template-columns:44px 1fr auto;align-items:baseline;gap:14px;padding:12px 16px;text-decoration:none;color:var(--fg);background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.contents-item:hover{border-color:var(--accent)}
.contents-item .num{font-weight:700;font-size:20px;color:var(--accent)}
.contents-item .name{font-size:clamp(16px,1.35vw,19px);font-weight:600}
.contents-item .count{font-size:13.5px;color:var(--muted);white-space:nowrap}
.slide-sources{margin:auto 0 0;font-size:13.5px;color:var(--muted);line-height:1.5}
.question+.slide-sources{margin-top:0}
.slide-sources a{color:var(--muted)}
.slide-sources a:hover{color:var(--accent)}
.points{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:10px}
.slide-body.with-figure .points,.slide-body.with-image .points,.slide-body.with-images .points{max-width:60ch}
.points.compact{flex-direction:row;flex-wrap:wrap;gap:6px 22px;max-width:none;margin-top:4px}
.points.compact li{font-size:clamp(16px,1.3vw,18.5px)}
.points li{position:relative;padding-left:20px;font-size:clamp(16px,1.3vw,18.5px);line-height:1.45}
.points li::before{content:'';position:absolute;left:0;top:.62em;width:7px;height:7px;border-radius:50%;background:var(--accent)}
.figure-wrap{margin:0;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:14px;box-shadow:var(--shadow)}
.figure-wrap svg{width:100%;height:auto;display:block;font-family:var(--font)}
.figure-wrap.image{padding:10px}
.figure-wrap.image img{width:100%;height:auto;display:block;border-radius:6px}
.figure-wrap figcaption{margin-top:8px;font-size:12.5px;color:var(--muted);line-height:1.4}
.course-code{margin:0;font-size:13px;letter-spacing:.1em;text-transform:uppercase;font-weight:600;color:var(--accent)}
.title-slide{justify-content:center;gap:16px}
.title-slide h1{font-size:clamp(32px,4.4vw,60px);max-width:22ch}
.title-slide .lead{color:var(--fg);font-size:clamp(18px,1.7vw,22px)}
.title-slide .points{border-top:1px solid var(--line-strong);padding-top:16px;max-width:50ch}
.title-slide .points li{font-size:15px;color:var(--muted)}
.title-slide .points li::before{width:6px;height:6px}
.title-slide .points li a{color:inherit;text-decoration:none;border-bottom:1px solid var(--line-strong)}
.title-slide .points li a:hover{color:var(--accent);border-bottom-color:var(--accent)}
.title-slide .logos{display:flex;align-items:center;flex-wrap:wrap;gap:14px 38px;margin-top:4px}
.title-slide .logos a{display:block;border-radius:4px}
.title-slide .logos a:hover img{opacity:.8}
.title-slide .logos img{display:block;width:auto;height:auto;max-height:56px;max-width:170px;transition:opacity .15s}
.title-slide .question{margin-top:18px}

/* question */
.question{margin-top:auto;padding:14px 16px;border-radius:11px;background:var(--accent-soft);border:1px solid var(--accent-border);border-left:3px solid var(--accent);display:flex;flex-direction:column;gap:10px}
.question-text{margin:0;font-size:16.5px;font-weight:500}
.question-label{display:inline-block;font-size:11px;letter-spacing:.1em;text-transform:uppercase;font-weight:600;color:var(--accent);margin-right:10px}
.choices{display:flex;flex-wrap:wrap;gap:8px}
.choice{text-align:left;background:var(--surface);font-weight:400;font-size:14px;padding:6px 12px}
.choice[aria-pressed=true]{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent);color:var(--accent)}
.choice.is-correct{border-color:var(--ok);background:var(--ok-soft);color:var(--ok);box-shadow:inset 0 0 0 1px var(--ok)}
.choice.is-correct::after{content:' ✓';font-weight:600}
.choice-note{margin:0;font-size:13.5px;color:var(--muted)}
.round-bar{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-size:13.5px;color:var(--muted)}
.round-badge{display:inline-block;font-size:11.5px;letter-spacing:.08em;text-transform:uppercase;font-weight:600;color:var(--accent);background:var(--surface);border:1px solid var(--accent-border);border-radius:999px;padding:2px 10px}
.round-badge.two{color:#fff;background:var(--accent);border-color:var(--accent)}
.second-round{font-size:13px}
.reveal{align-self:flex-start}
.answer{font-size:15.5px;line-height:1.5;padding-top:8px;border-top:1px solid var(--accent-border)}
.choices-print{margin:0;padding-left:20px;font-size:14px}
.choices-print .is-correct{font-weight:600;color:var(--ok)}

/* footer */
.course-footer{border-top:1px solid var(--line);background:var(--surface)}
.footer-toolbar{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:12px;padding:6px 22px;min-height:40px}
.chapter-position{display:flex;flex-direction:column;line-height:1.25;min-width:0}
#chapter-label{font-size:12.5px;font-weight:600;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
#chapter-position{font-size:11.5px;color:var(--muted)}
.footer-actions{display:flex;gap:6px}
#explain[aria-expanded=true]{background:var(--accent-soft);border-color:var(--accent);color:var(--accent)}
.slide-navigation{display:flex;align-items:center;justify-content:flex-end;gap:8px}
.slide-navigation button{width:30px;height:28px;padding:0;font-size:15px;line-height:1}
#position{font-size:12.5px;font-weight:500;color:var(--muted);min-width:5ch;text-align:center}
.explanation{margin:0;padding:12px 22px 14px;border-top:1px solid var(--line);max-height:34vh;overflow:auto;font-size:15px;line-height:1.55;background:var(--bg)}
.explanation h3{margin:0 0 6px;font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:var(--accent)}
.explanation p{margin:0 0 10px;text-align:justify;hyphens:auto;-webkit-hyphens:auto}
.explanation p:last-child{margin-bottom:0}
.footer-credit{display:flex;justify-content:space-between;gap:12px;padding:4px 22px 6px;font-size:12px;color:var(--muted);border-top:1px solid var(--line)}
.footer-credit a{color:inherit;text-decoration:none}
.footer-credit a:hover{color:var(--accent)}
.chapter-track{height:3px;background:var(--line)}
#progress{height:100%;width:0;background:var(--accent);transition:width .35s ease}

/* dialogs */
dialog{border:1px solid var(--line-strong);border-radius:14px;padding:24px 28px;max-width:min(760px,92vw);width:100%;max-height:88vh;background:var(--surface);color:var(--fg);box-shadow:0 30px 80px -30px rgba(15,30,60,.6)}
dialog::backdrop{background:rgba(15,20,28,.42)}
dialog h2{margin:0 0 14px;font-size:20px;letter-spacing:-.01em}
dialog .close{position:absolute;top:12px;right:12px;width:30px;height:30px;padding:0;font-size:18px;line-height:1;border-radius:50%;display:flex;align-items:center;justify-content:center}
dialog.compact{max-width:min(420px,92vw)}
#jump-form{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-size:14.5px}
#jump-form input{width:6em;font-size:16px}
button.primary{background:var(--accent);color:#fff;border-color:var(--accent)}
button.primary:hover{background:#154a8f;color:#fff}
#toc{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:16px 24px}
#toc section h3{margin:0 0 6px;font-size:13px;display:flex;gap:8px;align-items:baseline}
#toc section h3 .num{font-size:11px;font-weight:600;color:var(--accent)}
#toc a{display:block;font-size:13.5px;text-decoration:none;color:var(--fg);padding:2px 0 2px 8px;border-left:2px solid transparent}
#toc a:hover{color:var(--accent)}
#toc a.active{border-left-color:var(--accent);color:var(--accent);font-weight:600}
.study-links{display:flex;flex-wrap:wrap;gap:8px;margin:18px 0 12px;padding-top:14px;border-top:1px solid var(--line)}
.study-links a,.study-links button{font-size:13px;text-decoration:none;padding:5px 11px;border:1px solid var(--line-strong);border-radius:var(--radius-small);color:var(--fg);background:var(--surface)}
.study-links a:hover,.study-links button:hover{border-color:var(--accent);color:var(--accent)}
dialog details summary{cursor:pointer;font-size:13.5px;font-weight:500;color:var(--muted)}
#sources p{font-size:13px;margin:6px 0;line-height:1.45}
.button-link{display:inline-block;background:var(--accent);color:#fff;text-decoration:none;padding:7px 14px;border-radius:var(--radius-small);font-size:14px;font-weight:500}
.button-link.secondary{background:var(--surface);color:var(--accent);border:1px solid var(--accent)}
.notice{padding:12px 14px;border-radius:var(--radius);background:var(--accent-soft);border:1px solid var(--accent-border);font-size:14.5px;line-height:1.5}
.muted{color:var(--muted);font-size:13px}

/* labs */
.lab{margin-top:6px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;font-size:clamp(16px,1.3vw,18.5px);line-height:1.5}
.lab p{margin:0 0 8px}
.lab h3,.lab h4{margin:0 0 8px;font-size:inherit;font-weight:600}
.lab-controls,.controls{display:flex;flex-wrap:wrap;gap:10px 16px;align-items:end;margin-bottom:10px}
.lab-controls label,.controls label,.lab label{display:flex;flex-direction:column;gap:3px;font-size:inherit;color:var(--muted);font-weight:500}
.lab label input:not([type=range]):not([type=checkbox]),.lab label select,.lab label textarea{color:var(--fg);font-weight:400}
.lab label select,.lab label input:not([type=range]):not([type=checkbox]):not([type=radio]){box-sizing:border-box;height:2.25em}
.lab label:has(input[type=checkbox]),.lab label:has(input[type=radio]){flex-direction:row;align-items:center;gap:6px}
.lab-note{font-size:inherit;color:var(--muted)}
.lab-status,.status{font-size:inherit;padding:8px 10px;border-radius:var(--radius-small);background:var(--accent-soft);border:1px solid var(--accent-border);margin-top:8px}
.lab-chart{margin:8px 0}
.lab-chart svg,.figure svg{width:100%;height:auto;max-height:420px;display:block}
.lab svg,.lab svg text,.figure-wrap svg{font-family:var(--font)}
.lab-grid,.two-col{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:18px;align-items:start}
.lab-mount{min-height:40px}
.lab table{border-collapse:collapse;width:100%;font-size:inherit;margin:6px 0}
.lab th,.lab td{padding:5px 8px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
.lab th{font-weight:600;color:var(--muted);font-size:.85em;letter-spacing:.04em;text-transform:uppercase}
.lab pre,.lab code{font-family:var(--mono);font-size:14px}
.lab pre{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius-small);padding:10px 12px;overflow:auto;white-space:pre-wrap;max-height:320px;margin:6px 0}
.lab details{margin:6px 0}
.lab details summary{cursor:pointer;font-size:14px;font-weight:500;color:var(--accent)}
.lab canvas{border:1px solid var(--line-strong);border-radius:var(--radius-small);background:#fff;touch-action:none;max-width:100%}
.lab output{font-family:var(--mono);font-size:14px}
.lab .tag{display:inline-block;font-size:11px;letter-spacing:.08em;text-transform:uppercase;font-weight:600;color:var(--accent);background:var(--accent-soft);border-radius:999px;padding:2px 10px;margin-bottom:8px}
.lab .source-frame{border:1px solid var(--line-strong);border-radius:var(--radius-small);padding:10px;background:var(--bg);position:relative}
.lab .source-mark{position:absolute;width:14px;height:14px;border-radius:50%;background:var(--accent);border:2px solid #fff;box-shadow:0 0 0 2px var(--accent);transform:translate(-50%,-50%);pointer-events:none}
.lab .token-list{display:flex;flex-wrap:wrap;gap:6px;font-family:var(--mono);font-size:inherit;margin:8px 0}
.lab .token-list span{border:1px solid var(--line-strong);border-radius:4px;padding:3px 8px;background:var(--bg);text-align:center;line-height:1.3}
.lab .token-list small{font-size:12px;color:var(--muted)}
.lab .legend{display:flex;flex-wrap:wrap;gap:6px 18px;font-size:inherit;margin:0 0 6px}
.lab .legend span{display:inline-flex;align-items:center;gap:6px}
.lab .legend i{display:inline-block;width:12px;height:12px;border-radius:50%}
.lab .bars{display:grid;gap:8px;margin:6px 0}
.lab .bar-row{display:grid;grid-template-columns:minmax(6rem,auto) 1fr minmax(10rem,auto);gap:12px;align-items:center;font-size:15px}
.lab .bar-track{background:var(--accent-soft);border:1px solid var(--accent-border);height:1.4rem;border-radius:4px;overflow:hidden}
.lab .bar-fill{background:var(--accent);height:100%}
.lab button.ghost{border-color:transparent;color:var(--muted)}
.lab pre.trace{min-height:120px;max-height:260px}
.lab button{margin:2px 0;font-size:.9em}
.lab-placeholder{font-style:italic;color:var(--muted)}
body.reading .lab-snapshot img{max-height:70vh;width:auto;max-width:100%;margin:0 auto}

/* reading / print view */
body.reading main#slide{max-width:900px;gap:40px}
body.reading .slide.centered{align-items:flex-start;text-align:left}
body.reading .contents-grid{grid-template-columns:1fr;grid-auto-flow:row;grid-template-rows:none}
body.reading .slide{flex:0 0 auto;padding-bottom:36px;border-bottom:1px solid var(--line-strong);page-break-after:always}
body.reading .slide h1{font-size:30px}
body.reading .slide-body.with-figure,body.reading .slide-body.with-image,body.reading .slide-body.lab-split,body.reading .slide-body.with-figure.wide-text,body.reading .slide-body.with-figure.half{grid-template-columns:1fr}
body.reading .question{margin-top:12px}
body.reading .explanation.print{max-height:none;overflow:visible;padding:14px 16px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}
.reading-bar{display:flex;align-items:center;gap:14px;font-size:13px;color:var(--muted);padding-bottom:6px}
body.reading .course-footer .footer-toolbar,body.reading #explanation,body.reading .chapter-track{display:none}

@media (max-width:900px){
 .image-strip{grid-template-columns:1fr}
 .course-header{gap:10px;padding:0 14px}
 #chapter-nav a .name{display:none}
 #chapter-nav a{padding:0 6px}
 .skyline{display:none}
 .title-slide .logos{gap:10px 24px}
 .title-slide .logos img{max-height:40px;max-width:120px}
 .slide-body.with-figure,.slide-body.with-image,.slide-body.lab-split,.slide-body.with-figure.wide-text,.slide-body.with-figure.half{grid-template-columns:1fr}
 .contents-grid{grid-template-columns:1fr;grid-auto-flow:row;grid-template-rows:none}
 main#slide{padding:22px 16px 20px}
 .footer-toolbar{grid-template-columns:1fr auto;padding:6px 14px}
 .chapter-position{grid-column:1/-1;order:3}
 .footer-credit{flex-direction:column;gap:2px;padding:4px 14px 6px}
 dialog{padding:20px 18px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}
@page{size:A4 landscape;margin:12mm}
@media print{
 .course-header,.overall-track,.course-footer,dialog,.reading-bar,.skip{display:none!important}
 /* The screen layout is a fixed-height grid with a scrolling main; printed, that clips to one page. */
 html,body{height:auto;min-height:0;overflow:visible}
 body{background:#fff;display:block}
 a{color:inherit;text-decoration:none}
}
/* Print layout. app.js sets body.printing on beforeprint, measures every slide in this layout and
   zooms tall slides down to the printable height of a landscape A4 page (273 × 186 mm). Flex and
   grid containers fragment badly in print (blank pages), so slides are laid out as plain blocks. */
body.printing{font-size:11pt}
body.printing main#slide{width:273mm;max-width:none;padding:0;margin:0;display:block;overflow:visible;height:auto}
body.printing .slide{display:block;break-after:page;page-break-after:always;break-inside:avoid;border:none;padding:0;margin:0}
body.printing .slide:last-child{break-after:auto;page-break-after:auto}
body.printing .slide>*+*,body.printing .slide-body>*+*{margin-top:8px}
body.printing .slide h1{font-size:22pt}
body.printing .slide-body{display:block}
body.printing .points li{margin:2px 0}
body.printing .figure-wrap{padding:6px;box-shadow:none}
body.printing .figure-wrap svg{max-height:100mm;width:100%}
body.printing .figure-wrap.image img{max-height:100mm;width:auto;max-width:100%;margin:0 auto;object-fit:contain}
body.printing .slide-body.stacked .figure-wrap.image:only-child{width:100%}
body.printing .image-strip{display:grid;grid-template-columns:1fr 1fr;gap:8px}
body.printing .image-strip .figure-wrap.image img{max-height:75mm;aspect-ratio:auto}
body.printing .lab-snapshot img{max-height:110mm}
body.printing .links{grid-template-columns:1fr 1fr}
body.printing .question{background:#f3f6fa;padding:8px 12px}

/* Blue mode buttons of the gradient-descent lab (2D / 3D); the active one is filled. */
.mode-button{border-width:1.5px}
.mode-button:hover{filter:brightness(.92)}
.mode-button.is-active:hover{color:#fff}

/* link cards (chapter 6: incidents and reading list) */
.slide-body.with-links{display:flex;flex-direction:column;gap:14px}
.links{margin:0;padding:0;list-style:none;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px 16px}
.links li{display:flex;flex-direction:column;gap:4px;padding:12px 16px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius,10px);min-width:0}
.links .link-title{font-weight:600;font-size:clamp(16px,1.3vw,19px);line-height:1.3;color:var(--accent);text-decoration:none;overflow-wrap:anywhere}
.links .link-title:hover{text-decoration:underline}
.links .link-meta{font-size:clamp(13px,1vw,14.5px);color:var(--muted)}
.links li p{margin:0;font-size:clamp(14.5px,1.15vw,17px);line-height:1.4}
.links .link-url{font-size:12px;color:var(--muted);font-family:var(--mono);overflow-wrap:anywhere}
@media (max-width:900px){.links{grid-template-columns:1fr}}
.links li .link-text{display:flex;flex-direction:column;gap:4px;min-width:0}
.links li.wide{grid-column:1/-1;flex-direction:row;align-items:center;gap:20px}
.links li.wide .qr{width:clamp(110px,11vw,160px);height:auto;flex:none;background:#fff;padding:6px;border-radius:6px}