/* ═══════════════════════════════════════════════════════════
   SweatyOpossum design system — professional, accessible
   Palette: deep navy / slate + single teal accent
   WCAG 2.1 AA: all text ≥ 4.5:1 on its background
   ═══════════════════════════════════════════════════════════ */

:root {
  /* Light theme (default) */
  --bg:        #ffffff;
  --surface:   #f8fafc;
  --panel:     #ffffff;
  --border:    #dbe2ea;
  --text:      #182230;   /* ~14.7:1 on #fff */
  --muted:     #46546a;   /* ~7.6:1 on #fff */
  --accent:    #0e6f6a;   /* teal — 5.9:1 on #fff */
  --accent-ink:#0a5450;
  --accent-bg: #eef7f6;
  --navy:      #10233f;
  --navy-ink:  #ffffff;
  --navy-muted:#c3cfdd;   /* ≥7:1 on navy */
  --warn-bg:   #fff8eb;
  --warn-border:#e8d5a8;
  --warn-ink:  #6b4e0e;   /* ≥7:1 on warn-bg */
  --good:      #166534;
  --bad:       #b42318;
  --shadow:    0 1px 3px rgba(16,35,63,.08), 0 4px 14px rgba(16,35,63,.06);
  --radius:    10px;

  /* Spacing scale */
  --s1: 4px;  --s2: 8px;  --s3: 12px; --s4: 16px;
  --s5: 24px; --s6: 32px; --s7: 48px; --s8: 64px;

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto,
          "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:        #0f1a2b;
    --surface:   #14213619;
    --surface:   #142136;
    --panel:     #172943;
    --border:    #2b3d58;
    --text:      #e8edf4;   /* ~13:1 */
    --muted:     #a8b6c9;   /* ~7:1 */
    --accent:    #4fc4bc;   /* ~7.4:1 on #0f1a2b */
    --accent-ink:#7fd6d0;
    --accent-bg: #10304333;
    --accent-bg: rgba(79,196,188,.09);
    --navy:      #0b1626;
    --navy-ink:  #f2f6fa;
    --navy-muted:#b7c4d4;
    --warn-bg:   #2b2410;
    --warn-border:#5a4a1d;
    --warn-ink:  #ecd9a0;
    --good:      #6fce8f;
    --bad:       #f2917f;
    --shadow:    0 1px 3px rgba(0,0,0,.4);
  }
}

/* ── Reset & base ── */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: var(--font); font-size: 1.0625rem; line-height: 1.65;
}
img, svg { max-width: 100%; height: auto; }
h1, h2, h3, h4 { line-height: 1.25; margin: 0 0 var(--s4); font-weight: 700; letter-spacing: -.01em; }
h1 { font-size: clamp(1.75rem, 4vw, 2.4rem); }
h2 { font-size: clamp(1.35rem, 3vw, 1.7rem); margin-top: var(--s6); }
h3 { font-size: 1.18rem; margin-top: var(--s5); }
p, ul, ol { margin: 0 0 var(--s4); }
li { margin-bottom: var(--s2); }
a { color: var(--accent); text-underline-offset: 2px; }
a:hover { color: var(--accent-ink); }
code { font-family: var(--mono); font-size: .92em; background: var(--surface); border: 1px solid var(--border); border-radius: 4px; padding: 0 4px; }
hr { border: none; border-top: 1px solid var(--border); margin: var(--s6) 0; }

:focus-visible {
  outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 3px;
}

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 200;
  background: var(--accent); color: #fff; padding: var(--s3) var(--s4);
  border-radius: 0 0 var(--radius) 0; font-weight: 600;
}
.skip-link:focus { left: 0; color: #fff; }

.visually-hidden {
  position: absolute !important; width: 1px; height: 1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap;
}

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 var(--s4); }
.wrap-narrow { max-width: 760px; margin: 0 auto; padding: 0 var(--s4); }

html { scroll-behavior: smooth; }
html:focus-within { scroll-behavior: smooth; }

/* ── Header ── */
.site-header {
  background: var(--navy); color: var(--navy-ink);
  position: sticky; top: 0; z-index: 100;
  box-shadow: 0 1px 0 rgba(255,255,255,.06), 0 2px 12px rgba(6,14,26,.35);
}
.site-header .bar {
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--s4); padding: var(--s3) 0; flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: var(--s3); text-decoration: none; color: var(--navy-ink); }
.brand-mark {
  width: 38px; height: 38px; border-radius: 50%; background: #17564f;
  display: inline-flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.brand-name { font-weight: 700; font-size: 1.15rem; letter-spacing: .01em; }
.brand-tag { display: block; font-size: .78rem; color: var(--navy-muted); font-weight: 400; }
.site-nav ul { display: flex; flex-wrap: wrap; gap: var(--s2); list-style: none; margin: 0; padding: 0; }
.site-nav a {
  display: block; color: var(--navy-muted); text-decoration: none;
  padding: var(--s2) var(--s3); border-radius: 6px; font-weight: 500; font-size: .95rem;
}
.site-nav a:hover { color: var(--navy-ink); background: rgba(255,255,255,.08); }
.site-nav a[aria-current="page"], .site-nav a[aria-current="true"] {
  color: var(--navy-ink); background: rgba(255,255,255,.12);
}

/* ── First-visit notice ── */
.edu-banner {
  background: var(--warn-bg); border-bottom: 1px solid var(--warn-border);
  color: var(--warn-ink); padding: var(--s2) 0; font-size: .92rem;
}
.edu-banner .wrap { display: flex; align-items: center; gap: var(--s3); justify-content: center; flex-wrap: wrap; }
.edu-banner button {
  background: none; border: 1px solid currentColor; color: inherit;
  border-radius: 6px; padding: 2px 10px; cursor: pointer; font: inherit; font-size: .85rem;
}
.edu-banner[hidden] { display: none; }

/* ── Hero / sections ── */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(ellipse 80% 60% at 85% -10%, rgba(79,196,188,.22), transparent 60%),
    radial-gradient(ellipse 60% 50% at -10% 110%, rgba(23,86,79,.55), transparent 65%),
    linear-gradient(160deg, #10233f 0%, #0d2a41 55%, #0f3540 100%);
  color: var(--navy-ink); padding: var(--s8) 0;
}
.hero h1 { color: var(--navy-ink); max-width: 22ch; font-size: clamp(2rem, 5vw, 2.9rem); }
.hero p.lead { color: var(--navy-muted); font-size: 1.15rem; max-width: 56ch; }
.hero-actions { display: flex; gap: var(--s3); flex-wrap: wrap; margin-top: var(--s5); }
.btn-lg { padding: 13px 28px; font-size: 1.05rem; }
.btn-hero { border-color: #7fd0c9; color: #d7e4ef; }
.btn-hero:hover { background: rgba(127,208,201,.12); color: #fff; }
.hero-chips { list-style: none; display: flex; flex-wrap: wrap; gap: var(--s2); margin: var(--s5) 0 0; padding: 0; }
.hero-chips li {
  border: 1px solid rgba(127,208,201,.4); color: #a9dcd7; border-radius: 999px;
  padding: 3px 14px; font-size: .85rem; font-weight: 600;
}
.hero-stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--s4); margin-top: var(--s7); padding-top: var(--s5);
  border-top: 1px solid rgba(255,255,255,.14);
}
.hero-stats .n { display: block; font-size: 2rem; font-weight: 800; color: #7fd0c9; font-variant-numeric: tabular-nums; line-height: 1.1; }
.hero-stats .l { color: var(--navy-muted); font-size: .9rem; }
.section { padding: var(--s7) 0; }
.section-alt { background: var(--surface); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.eyebrow {
  font-size: .82rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  color: var(--accent); margin-bottom: var(--s2);
}
.hero .eyebrow { color: #7fd0c9; }

/* ── Cards & grids ── */
.grid { display: grid; gap: var(--s4); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.card {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: var(--radius); padding: var(--s5); box-shadow: var(--shadow);
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
a.card { display: block; text-decoration: none; color: var(--text); position: relative; }
a.card:hover, a.card:focus-visible {
  border-color: var(--accent); color: var(--text);
  transform: translateY(-3px);
  box-shadow: 0 4px 8px rgba(16,35,63,.10), 0 12px 28px rgba(16,35,63,.12);
}
a.card h3 { color: var(--accent); margin-top: 0; }
.card h3 { margin-top: 0; }
.card-cta { display: flex; align-items: center; justify-content: space-between; margin-bottom: 0; color: var(--accent-ink); }
.card-cta .go { font-size: 1.2rem; transition: transform .18s ease; }
a.card:hover .card-cta .go { transform: translateX(4px); }
.path-card { padding-top: var(--s6); }
.path-num {
  position: absolute; top: var(--s4); right: var(--s4);
  width: 34px; height: 34px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--accent-bg); color: var(--accent-ink);
  font-weight: 800; font-size: 1rem; border: 1px solid var(--accent);
}

/* ── Buttons ── */
.btn {
  display: inline-block; background: var(--accent); color: #fff;
  border: 1px solid transparent; border-radius: 8px; padding: 10px 22px;
  font: inherit; font-weight: 600; text-decoration: none; cursor: pointer;
  transition: transform .15s ease, background-color .15s ease, box-shadow .15s ease;
}
.btn:hover { background: var(--accent-ink); color: #fff; transform: translateY(-1px); box-shadow: 0 4px 12px rgba(14,111,106,.28); }
.btn:active { transform: none; }
.btn-outline { background: transparent; color: var(--accent); border-color: var(--accent); }
.btn-outline:hover { background: var(--accent-bg); color: var(--accent-ink); }
@media (prefers-color-scheme: dark) {
  .btn { color: #08211f; }
  .btn:hover { color: #08211f; background: var(--accent-ink); }
}

/* ── Badges ── */
.badge {
  display: inline-block; font-size: .78rem; font-weight: 700;
  border-radius: 999px; padding: 2px 12px; border: 1px solid var(--border);
  background: var(--surface); color: var(--muted); vertical-align: middle;
}
.badge-beginner     { background: var(--accent-bg); color: var(--accent-ink); border-color: transparent; }
.badge-intermediate { background: #eef2ff; color: #3730a3; border-color: transparent; }
.badge-advanced     { background: #fdf2f2; color: #9b1c1c; border-color: transparent; }
@media (prefers-color-scheme: dark) {
  .badge-intermediate { background: #2b3568; color: #c7d2fe; }
  .badge-advanced     { background: #4c1f1f; color: #f4c7c3; }
}

/* ── Article layout ── */
.article-meta {
  display: flex; flex-wrap: wrap; gap: var(--s3); align-items: center;
  color: var(--muted); font-size: .92rem; margin-bottom: var(--s5);
}
article.lesson { padding: var(--s7) 0; }
article.lesson > .wrap-narrow > p:first-of-type { font-size: 1.1rem; }

.takeaways {
  background: var(--accent-bg); border: 1px solid var(--accent);
  border-radius: var(--radius); padding: var(--s5); margin: var(--s5) 0;
}
.takeaways h2 { margin: 0 0 var(--s3); font-size: 1.1rem; color: var(--accent-ink); }
.takeaways ul { margin: 0; padding-left: 20px; }

.misconceptions { margin: var(--s6) 0; }
.misconceptions .item {
  border-left: 4px solid var(--warn-border); background: var(--surface);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: var(--s4); margin-bottom: var(--s3);
}
.misconceptions .claim { font-weight: 700; margin-bottom: var(--s1); }

.worked-example {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: var(--s5); margin: var(--s5) 0;
}
.worked-example h3:first-child, .worked-example h2:first-child { margin-top: 0; }

/* ── Tables ── */
.table-scroll { overflow-x: auto; margin: var(--s4) 0; }
table { border-collapse: collapse; width: 100%; font-size: .95rem; }
caption { text-align: left; font-weight: 600; padding-bottom: var(--s2); color: var(--muted); font-size: .9rem; }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border); }
th { background: var(--surface); font-size: .85rem; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

/* ── Disclaimers ── */
.edu-disclaimer {
  border: 1px solid var(--warn-border); background: var(--warn-bg);
  color: var(--warn-ink); border-radius: var(--radius);
  padding: var(--s4) var(--s5); margin: var(--s6) 0; font-size: .92rem;
}
.edu-disclaimer strong { display: block; margin-bottom: var(--s1); }
.calc-caveat {
  display: flex; gap: var(--s2); align-items: flex-start;
  background: var(--warn-bg); border: 1px solid var(--warn-border); color: var(--warn-ink);
  border-radius: 8px; padding: var(--s2) var(--s3); font-size: .88rem; margin-top: var(--s3);
}
.data-note { color: var(--muted); font-size: .85rem; margin-top: var(--s2); }

/* ── Glossary term links ── */
a.term {
  color: var(--accent); text-decoration: underline dotted; position: relative;
}
a.term::after {
  content: attr(data-tip);
  position: absolute; left: 0; bottom: calc(100% + 6px); z-index: 50;
  width: min(320px, 80vw); background: var(--navy); color: var(--navy-ink);
  border-radius: 8px; padding: var(--s3); font-size: .85rem; line-height: 1.5;
  box-shadow: var(--shadow); opacity: 0; visibility: hidden; pointer-events: none;
  transition: opacity .15s;
}
a.term:hover::after, a.term:focus-visible::after { opacity: 1; visibility: visible; }

/* ── Quiz ── */
.quiz { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: var(--s5); margin: var(--s6) 0; }
.quiz h2 { margin-top: 0; font-size: 1.2rem; }
.quiz fieldset { border: none; margin: 0 0 var(--s4); padding: 0; }
.quiz legend { font-weight: 600; margin-bottom: var(--s2); padding: 0; }
.quiz label { display: block; padding: var(--s2) var(--s3); border: 1px solid var(--border); border-radius: 8px; margin-bottom: var(--s2); background: var(--panel); cursor: pointer; transition: border-color .12s ease, background-color .12s ease; }
.quiz label:hover { border-color: var(--accent); }
.quiz label:has(input:checked) { border-color: var(--accent); background: var(--accent-bg); }
.quiz input[type="radio"] { margin-right: var(--s2); accent-color: var(--accent); }
.quiz .q-result { font-size: .92rem; margin: var(--s2) 0 0; display: none; }
.quiz .q-result.ok { color: var(--good); display: block; }
.quiz .q-result.no { color: var(--bad); display: block; }
.quiz details { margin-top: var(--s2); font-size: .92rem; }
.quiz .quiz-score { font-weight: 700; margin-top: var(--s3); }

/* ── Progress ── */
.progress-track { background: var(--border); border-radius: 999px; height: 10px; overflow: hidden; }
.progress-fill { background: var(--accent); height: 100%; width: 0; }
.path-progress { display: flex; align-items: center; gap: var(--s3); margin: var(--s4) 0; font-size: .92rem; color: var(--muted); }
.path-progress .progress-track { flex: 1; }
.lesson-list { list-style: none; margin: 0; padding: 0; counter-reset: lesson; }
.lesson-list li { counter-increment: lesson; margin-bottom: var(--s3); }
.lesson-list a {
  display: flex; gap: var(--s4); align-items: flex-start; text-decoration: none;
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: var(--s4); color: var(--text);
  transition: transform .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.lesson-list a:hover, .lesson-list a:focus-visible {
  border-color: var(--accent); transform: translateX(4px);
  box-shadow: 0 2px 8px rgba(16,35,63,.10);
}
.lesson-list a::before {
  content: counter(lesson); font-weight: 800; color: var(--accent-ink);
  background: var(--accent-bg); border: 1px solid var(--accent);
  width: 30px; height: 30px; min-width: 30px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  font-size: .92rem; margin-top: 2px;
}
.lesson-list .done { border-left: 4px solid var(--good); }
.lesson-list .done::after { content: "✓ completed"; color: var(--good); font-weight: 600; font-size: .85rem; margin-left: auto; white-space: nowrap; }
.lesson-list .done::before { content: "✓"; background: var(--good); color: #fff; border-color: var(--good); }

/* ── Continue-learning callout (JS-injected on the hub) ── */
.resume-callout {
  display: flex; align-items: center; gap: var(--s3); flex-wrap: wrap;
  background: var(--accent-bg); border: 1px solid var(--accent);
  border-radius: var(--radius); padding: var(--s4) var(--s5); margin: var(--s4) 0 var(--s5);
}
.resume-callout .eyebrow { margin: 0; }
.resume-callout a { font-weight: 700; }

/* ── Article table of contents ── */
.toc {
  background: var(--surface); border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius); padding: var(--s4) var(--s5); margin: var(--s5) 0;
}
.toc-title {
  font-size: .82rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  color: var(--muted); margin: 0 0 var(--s2);
}
.toc ol { margin: 0; padding-left: 20px; columns: 2; column-gap: var(--s6); }
.toc li { margin-bottom: var(--s1); break-inside: avoid; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }
.toc a.active { color: var(--accent-ink); font-weight: 700; }
@media (max-width: 620px) { .toc ol { columns: 1; } }

/* ── Reading progress bar ── */
.read-progress {
  position: fixed; top: 0; left: 0; right: 0; height: 4px; z-index: 300;
  background: transparent; pointer-events: none;
}
.read-progress-fill { height: 100%; width: 0; background: var(--accent); transition: width .1s linear; }

/* ── Prev/next lesson cards ── */
.lesson-nav { display: grid; grid-template-columns: 1fr 1fr; gap: var(--s4); margin-top: var(--s6); }
@media (max-width: 560px) { .lesson-nav { grid-template-columns: 1fr; } }
.lesson-nav-card {
  display: flex; flex-direction: column; gap: var(--s1); text-decoration: none;
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: var(--s4); transition: transform .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.lesson-nav-card:hover, .lesson-nav-card:focus-visible {
  border-color: var(--accent); transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(16,35,63,.10);
}
.lesson-nav-card .dir { font-size: .8rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); }
.lesson-nav-card .t { font-weight: 700; color: var(--accent); }
.lesson-nav-card.is-next { text-align: right; align-items: flex-end; }

/* ── Back to top ── */
.back-to-top {
  position: fixed; right: var(--s4); bottom: var(--s4); z-index: 150;
  width: 46px; height: 46px; border-radius: 50%;
  background: var(--accent); color: #fff; border: none; cursor: pointer;
  font-size: 1.25rem; line-height: 1; box-shadow: 0 4px 14px rgba(16,35,63,.3);
  opacity: 0; visibility: hidden; transform: translateY(8px);
  transition: opacity .2s, transform .2s, visibility .2s;
}
.back-to-top.show { opacity: 1; visibility: visible; transform: none; }
.back-to-top:hover { background: var(--accent-ink); }

/* ── Calculators / tools ── */
.tool-panel { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: var(--s5); box-shadow: var(--shadow); margin: var(--s5) 0; }
.tool-controls { display: grid; gap: var(--s4); grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); margin-bottom: var(--s4); }
.field label { display: block; font-weight: 600; font-size: .92rem; margin-bottom: var(--s1); }
.field .hint { font-weight: 400; color: var(--muted); }
.field input[type="number"], .field input[type="text"], .field select {
  width: 100%; padding: 9px 12px; border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font: inherit;
}
.field input[type="range"] { width: 100%; accent-color: var(--accent); }
.stat { border-left: 4px solid var(--accent); padding-left: var(--s3); }
.stat .v { font-size: 1.5rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.stat .l { color: var(--muted); font-size: .85rem; }
.stat-row { display: grid; gap: var(--s4); grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); margin: var(--s4) 0; }
.chart-box svg { display: block; width: 100%; height: auto; }
.chip { display:inline-flex; align-items:center; gap:6px; background: var(--accent-bg); color: var(--accent-ink); border:1px solid var(--accent); border-radius:999px; padding:2px 10px; font-size:.88rem; }
.chip button { background:none; border:none; color:inherit; cursor:pointer; font-size:1rem; line-height:1; padding:0; }

/* ── Glossary page ── */
.glossary-search { margin: var(--s5) 0; }
.glossary-search input { width: 100%; max-width: 420px; padding: 10px 14px; border: 1px solid var(--border); border-radius: 8px; font: inherit; background: var(--bg); color: var(--text); }
.glossary-letters { display: flex; flex-wrap: wrap; gap: var(--s1); list-style: none; padding: 0; margin: var(--s4) 0; }
.glossary-letters a { display: inline-block; min-width: 32px; text-align: center; padding: 4px; border: 1px solid var(--border); border-radius: 6px; text-decoration: none; }
dl.glossary dt { font-weight: 700; font-size: 1.05rem; margin-top: var(--s5); }
dl.glossary dd { margin: var(--s1) 0 0; color: var(--text); }

/* ── Footer ── */
.site-footer { background: var(--navy); color: var(--navy-muted); margin-top: var(--s8); padding: var(--s7) 0 var(--s5); font-size: .92rem; }
.site-footer a { color: var(--navy-ink); }
.site-footer .cols { display: grid; gap: var(--s5); grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); margin-bottom: var(--s5); }
.site-footer h2 { font-size: .85rem; text-transform: uppercase; letter-spacing: .07em; color: var(--navy-ink); margin: 0 0 var(--s3); }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: var(--s2); }
.footer-disclaimer { border-top: 1px solid rgba(255,255,255,.15); padding-top: var(--s4); }

/* ── Breadcrumbs ── */
.breadcrumbs { font-size: .88rem; color: var(--muted); padding: var(--s4) 0 0; }
.breadcrumbs ol { list-style: none; display: flex; flex-wrap: wrap; gap: var(--s1); margin: 0; padding: 0; }
.breadcrumbs li + li::before { content: "›"; margin: 0 var(--s2); color: var(--muted); }

/* ── Motion ── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}

@media print {
  .site-header, .site-footer, .edu-banner, .quiz, .skip-link { display: none; }
}