diff --git a/.github/workflows/render-and-publish.yml b/.github/workflows/render-and-publish.yml
index de274ae3..62a3609a 100644
--- a/.github/workflows/render-and-publish.yml
+++ b/.github/workflows/render-and-publish.yml
@@ -91,6 +91,7 @@ jobs:
           path: site/_site
 
   deploy:
+    if: github.repository == 'ClojureCivitas/clojurecivitas.github.io'
     needs: build
     permissions:
       pages: write
diff --git a/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_base.css b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_base.css
new file mode 100644
index 00000000..2c18db1a
--- /dev/null
+++ b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_base.css
@@ -0,0 +1 @@
+:root{--ve-accent:#1464b5;--ve-accent-soft:#e5f1fb;--ve-warm:#9a4b00;--ve-warm-soft:#fff0df;--ve-purple:#694aa6;--ve-muted:#4f5b66}.quarto-dark{--ve-accent:#73b7ff;--ve-accent-soft:#173653;--ve-warm:#ffc27a;--ve-warm-soft:#4a2d12;--ve-purple:#c5a7ff;--ve-muted:#b9c7d2}#title-block-header{padding-top:.75rem}#title-block-header h1{line-height:1.15;overflow-wrap:anywhere}mjx-container[display=true]{max-width:100%;overflow-x:auto;overflow-y:hidden}.ve-callout{border:1px solid color-mix(in srgb,var(--ve-accent) 45%,var(--bs-border-color,#dee2e6));border-left:4px solid var(--ve-accent);background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-accent) 10%);color:var(--bs-body-color,#212529);padding:1rem 1.15rem;margin:1.4rem 0;border-radius:.35rem}.ve-callout.provisional{border-color:color-mix(in srgb,var(--ve-warm) 60%,var(--bs-border-color,#dee2e6));border-left-color:var(--ve-warm);background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-warm) 10%)}.ve-callout strong{display:block;margin-bottom:.3rem}.ve-callout p:last-child{margin-bottom:0}.ve-grid,.ve-definition-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,15rem),1fr));gap:.75rem;margin:1.25rem 0}.ve-card,.ve-definition{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.5rem;padding:.85rem;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529);overflow-wrap:anywhere}.ve-card h3{font-size:1rem;margin-top:0}.ve-definition dt{font-weight:800;color:var(--ve-accent)}.ve-definition dd{margin:.25rem 0 0}.ve-table-wrap{max-width:100%;overflow-x:auto;margin:1.25rem 0}.ve-table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums}.ve-table th,.ve-table td{padding:.55rem .7rem;border-bottom:1px solid var(--bs-border-color,#dee2e6);text-align:right;white-space:nowrap}.ve-table th:first-child,.ve-table td:first-child{text-align:left}.ve-table thead th{border-bottom:2px solid var(--bs-border-color,#adb5bd)}.ve-figure{margin:1.5rem 0;padding:1rem;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.5rem;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-figure svg{display:block;width:100%;height:auto}.ve-caption,.ve-note{font-size:.9rem;color:var(--ve-muted);margin:.75rem 0 0}.ve-simulator{margin:1.5rem 0}.ve-reading-guide{border-left:4px solid var(--ve-accent);padding:.2rem 0 .2rem 1rem;margin:1rem 0}.ve-reading-guide h3{font-size:1rem;margin:.1rem 0 .35rem}.ve-reading-guide ul{margin-bottom:.2rem}.ve-hierarchy{display:grid;grid-template-columns:minmax(8rem,.7fr) auto minmax(0,1.5fr);gap:.7rem;align-items:center}.ve-hierarchy-node{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.7rem;text-align:center;background:var(--bs-body-bg,#fff);overflow-wrap:anywhere}.ve-hierarchy-node strong{display:block;color:var(--ve-accent)}.ve-hierarchy-arrow{font-size:1.5rem;color:var(--ve-accent);font-weight:800}.ve-form-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.5rem}.ve-sense-gap{grid-column:1/-1;border:2px dashed var(--ve-warm);border-radius:.45rem;padding:.65rem;text-align:center;color:var(--bs-body-color,#212529);background:color-mix(in srgb,var(--bs-body-bg,#fff) 92%,var(--ve-warm) 8%)}.ve-sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@media(max-width:767px){.ve-hierarchy{grid-template-columns:minmax(0,1fr)}.ve-hierarchy-arrow{transform:rotate(90deg);text-align:center}.ve-form-list{grid-template-columns:minmax(0,1fr)}}@media(max-width:575px){.ve-table th,.ve-table td{padding:.45rem}.ve-figure{padding:.65rem}}
diff --git a/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_round.css b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_round.css
new file mode 100644
index 00000000..dabb1dfa
--- /dev/null
+++ b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_round.css
@@ -0,0 +1 @@
+.ve-round-shell,.ve-stop-shell{min-width:0;border:1px solid var(--bs-border-color,#ced4da);border-radius:.65rem;padding:clamp(.8rem,3vw,1.3rem);background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-round-shell h3,.ve-stop-shell h3{margin-top:0}.ve-round-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:.55rem;margin:1rem 0}.ve-round-card{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.65rem;background:color-mix(in srgb,var(--bs-body-bg,#fff) 94%,var(--ve-accent) 6%);overflow-wrap:anywhere}.ve-round-card strong,.ve-round-card span,.ve-round-card small{display:block}.ve-round-card small{color:var(--ve-muted);margin-top:.25rem}.ve-round-progress{width:100%;height:.55rem;accent-color:var(--ve-accent)}.ve-round-status{min-height:2.8rem;font-variant-numeric:tabular-nums}.ve-stop-banner{display:flex;align-items:baseline;gap:.35rem;flex-wrap:wrap;border-left:4px solid var(--ve-accent);border-radius:.35rem;padding:.65rem .8rem;margin:.8rem 0;background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-accent) 10%)}.ve-stop-banner.is-counterfactual{border-left-color:var(--ve-warm);background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-warm) 10%)}.ve-stop-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,14rem),1fr));gap:.8rem;margin:1rem 0}.ve-stop-field{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.65rem}.ve-stop-field>div{display:flex;justify-content:space-between;align-items:baseline;gap:.5rem}.ve-stop-field label{font-weight:700}.ve-stop-field output{font-variant-numeric:tabular-nums;color:var(--ve-muted);text-align:right}.ve-stop-field input{width:100%;accent-color:var(--ve-accent)}.ve-stop-result{border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.75rem;margin:1rem 0}.ve-stop-result ul{margin:.5rem 0 0}.ve-sampling-button:disabled{opacity:.5;cursor:not-allowed}.ve-stop-field input:focus-visible{outline:3px solid color-mix(in srgb,var(--ve-accent) 50%,transparent);outline-offset:3px}@media(max-width:767px){.ve-round-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:400px){.ve-round-grid{grid-template-columns:minmax(0,1fr)}}
diff --git a/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_sampler.css b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_sampler.css
new file mode 100644
index 00000000..72e1ddae
--- /dev/null
+++ b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_sampler.css
@@ -0,0 +1 @@
+.ve-posterior-sampler{border:1px solid var(--bs-border-color,#ced4da);border-radius:.65rem;padding:clamp(.8rem,3vw,1.3rem);min-width:0;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-sampling-intro{max-width:50rem}.ve-sampling-controls{display:flex;align-items:end;justify-content:space-between;gap:1rem;flex-wrap:wrap;margin:1rem 0}.ve-rate-fieldset{border:0;padding:0;margin:0;min-width:0}.ve-rate-fieldset legend{font-size:.85rem;font-weight:700;margin-bottom:.4rem}.ve-button-row{display:flex;gap:.5rem;flex-wrap:wrap}.ve-sampling-button{border:1px solid var(--bs-border-color,#6c757d);border-radius:.35rem;padding:.55rem .85rem;font-weight:600;cursor:pointer;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-sampling-button[aria-pressed=true],.ve-sampling-button.ve-primary{border-color:#1464b5;background:#1464b5;color:#fff}.quarto-dark .ve-sampling-button[aria-pressed=true],.quarto-dark .ve-sampling-button.ve-primary{border-color:#73b7ff;background:#73b7ff;color:#10212b}.ve-sampling-button:focus-visible{outline:3px solid color-mix(in srgb,var(--ve-accent) 45%,transparent);outline-offset:2px}.ve-sampling-progress{width:100%;height:.55rem;accent-color:var(--ve-accent)}.ve-sampling-grid{display:grid;grid-template-columns:minmax(0,1fr);gap:1rem;margin-top:1rem}.ve-sample-panel{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.5rem;padding:clamp(.65rem,2vw,1rem);margin:0;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-sample-panel h4{font-size:1rem;margin:0 0 .25rem}.ve-sample-panel svg{display:block;width:100%;height:auto}.ve-sample-stat{font-variant-numeric:tabular-nums;margin:.2rem 0 .65rem}.ve-sample-note{font-size:.85rem;color:var(--ve-muted);margin:.5rem 0 0}.ve-empty-sample{display:grid;place-items:center;min-height:13rem;border:1px dashed var(--bs-border-color,#adb5bd);border-radius:.35rem;color:var(--ve-muted);text-align:center;padding:1rem}.ve-sampling-status{font-variant-numeric:tabular-nums;margin:.4rem 0}.ve-dot{fill:var(--ve-accent);fill-opacity:.72}.ve-dot-latest{fill:var(--ve-warm);stroke:var(--bs-body-bg,#fff);stroke-width:1.5}.ve-sample-axis{stroke:currentColor;stroke-opacity:.45}.ve-sample-guide{stroke:currentColor;stroke-opacity:.1}.ve-latest-line{stroke:var(--ve-accent);stroke-width:5;stroke-linecap:round}.ve-latest-dot{fill:var(--ve-warm);stroke:var(--bs-body-bg,#fff);stroke-width:2}.ve-draw-breakdown{width:100%;border-collapse:collapse;font-size:.82rem;font-variant-numeric:tabular-nums;margin-top:.75rem}.ve-draw-breakdown th,.ve-draw-breakdown td{padding:.35rem .45rem;border-bottom:1px solid var(--bs-border-color,#dee2e6);text-align:right;white-space:nowrap}.ve-draw-breakdown th:first-child{text-align:left}.ve-draw-breakdown-wrap{max-width:100%;overflow-x:auto}@media(max-width:575px){.ve-sampling-controls{align-items:stretch}.ve-sampling-controls>.ve-button-row{width:100%}.ve-sampling-controls>.ve-button-row .ve-sampling-button{flex:1}.ve-sampling-button{padding:.55rem .7rem}}
diff --git a/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_series.css b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_series.css
new file mode 100644
index 00000000..eedc31ed
--- /dev/null
+++ b/resources/language_learning/vocabulary_estimation/beta_binomial_first_pass_series.css
@@ -0,0 +1 @@
+.series-toc{min-width:0;border:1px solid var(--bs-border-color,#ced4da);border-radius:.6rem;padding:clamp(.85rem,3vw,1.2rem);margin:0 0 1.4rem;background:var(--bs-body-bg,#fff)}.series-toc h2{font-size:1.2rem;margin:0 0 .55rem}.series-toc p{margin:0 0 .7rem}.series-toc ol{margin:0;padding-left:1.45rem}.series-toc li{padding:.18rem .45rem}.series-status{display:inline-block;margin-left:.35rem;font-size:.7rem;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--ve-muted)}.series-current{margin:.35rem 0 .35rem -.7rem;border-left:4px solid var(--ve-accent);border-radius:.4rem;padding:.6rem .75rem!important;background:color-mix(in srgb,var(--bs-body-bg,#fff) 84%,var(--ve-accent) 16%);box-shadow:inset 0 0 0 1px color-mix(in srgb,var(--ve-accent) 35%,transparent);font-weight:700}.series-current>a{color:var(--ve-accent)}.series-current .series-status{border-radius:999px;padding:.18rem .48rem;background:var(--ve-accent);color:#fff}.quarto-dark .series-current .series-status{color:#10212b}
diff --git a/resources/language_learning/vocabulary_estimation/math_explanations.js b/resources/language_learning/vocabulary_estimation/math_explanations.js
new file mode 100644
index 00000000..88a13245
--- /dev/null
+++ b/resources/language_learning/vocabulary_estimation/math_explanations.js
@@ -0,0 +1,350 @@
+(() => {
+  const initialise = () => {
+    const globalButton = document.getElementById('article-explanations-toggle');
+    if (!globalButton || globalButton.dataset.initialized === 'true') return;
+
+    const articleMain = document.getElementById('quarto-document-content') || document.querySelector('main');
+    const marginQuery = window.matchMedia('(min-width: 1280px)');
+    const mathRegistries = Array.from(document.querySelectorAll('.math-explanation-registry'));
+    const termRegistries = Array.from(document.querySelectorAll('.term-explanation-registry'));
+    const codeDetails = Array.from(document.querySelectorAll('details.article-code-detail'));
+    const codeAction = document.getElementById('article-code-action');
+    const codeButton = document.getElementById('article-code-toggle');
+    const codeStatus = document.getElementById('article-code-status');
+
+    const makeHelpButton = ({label, controls, classes = []}) => {
+      const help = document.createElement('button');
+      help.type = 'button';
+      help.className = ['article-help-icon', ...classes].join(' ');
+      help.textContent = '?';
+      help.setAttribute('aria-label', label);
+      help.setAttribute('title', label);
+      help.setAttribute('aria-controls', controls.join(' '));
+      help.setAttribute('aria-expanded', 'false');
+      return help;
+    };
+
+    const ensureLayout = (anchor) => {
+      const existing = anchor.closest('.article-explanation-layout');
+      if (existing && existing.querySelector(':scope > .article-explanation-anchor') === anchor) {
+        return existing;
+      }
+      const layout = document.createElement('div');
+      layout.className = 'article-explanation-layout';
+      const slot = document.createElement('div');
+      slot.className = 'article-explanation-slot';
+      anchor.classList.add('article-explanation-anchor');
+      anchor.parentElement.insertBefore(layout, anchor);
+      layout.appendChild(anchor);
+      layout.appendChild(slot);
+      return layout;
+    };
+
+    const layoutSlot = (layout) => layout.querySelector(':scope > .article-explanation-slot');
+    const containsDisplayEquation = (node) => Boolean(
+      node && node.querySelector('span.math.display, mjx-container[display=true]')
+    );
+    const precedingEquation = (registry) => {
+      let cursor = registry;
+      for (let depth = 0; cursor && cursor.parentElement && depth < 4; depth += 1) {
+        let candidate = cursor.previousElementSibling;
+        while (candidate) {
+          if (containsDisplayEquation(candidate)) return candidate;
+          candidate = candidate.previousElementSibling;
+        }
+        if (cursor.parentElement.matches('section')) break;
+        cursor = cursor.parentElement;
+      }
+      return null;
+    };
+
+    mathRegistries.forEach((registry, registryIndex) => {
+      const items = Array.from(registry.querySelectorAll(':scope > details.article-explanation'));
+      const anchor = precedingEquation(registry);
+      if (!anchor || items.length === 0) return;
+      const accentClass = `accent-${(registryIndex % 6) + 1}`;
+      const layout = ensureLayout(anchor);
+      layout.classList.add('equation-explanation-layout');
+      const slot = layoutSlot(layout);
+      items.forEach((item) => {
+        item.classList.add(accentClass);
+        slot.appendChild(item);
+      });
+      anchor.classList.add('equation-help-anchor');
+      const title = registry.dataset.explanationTitle || 'this equation';
+      const help = makeHelpButton({
+        label: `Explain ${title}`,
+        controls: items.map((item) => item.id),
+        classes: ['equation-help-icon', accentClass]
+      });
+      anchor.appendChild(help);
+      registry.remove();
+    });
+
+    const excludedTextNode = (node) => Boolean(node.parentElement && node.parentElement.closest(
+      'script,style,pre,code,svg,details,.article-explanations-toolbar,.article-explanation-registry,.article-help-icon'
+    ));
+    const normaliseTerm = (text) => text.toLocaleLowerCase().replace(/[‐‑‒–—]/g, '-');
+    const isBoundary = (character) => !character || !/[A-Za-z0-9‐‑‒–—-]/.test(character);
+    const firstTermMatch = (root, text) => {
+      const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT);
+      const needle = normaliseTerm(text);
+      let node;
+      while ((node = walker.nextNode())) {
+        if (excludedTextNode(node)) continue;
+        const haystack = normaliseTerm(node.nodeValue || '');
+        let index = haystack.indexOf(needle);
+        while (index >= 0) {
+          const afterIndex = index + needle.length;
+          const plural = haystack[afterIndex] === 's' && isBoundary(haystack[afterIndex + 1]);
+          if (isBoundary(haystack[index - 1]) && (isBoundary(haystack[afterIndex]) || plural)) {
+            return {node, index, length: needle.length + (plural ? 1 : 0)};
+          }
+          index = haystack.indexOf(needle, index + 1);
+        }
+      }
+      return null;
+    };
+    const anchorBlockFor = (node) => node.parentElement?.closest('p,blockquote,li,figcaption,h2,h3,h4') || node.parentElement;
+    const appendInlineHelp = (match, help) => {
+      const after = match.node.splitText(match.index + match.length);
+      after.parentNode.insertBefore(help, after);
+    };
+
+    termRegistries.forEach((registry) => {
+      const items = Array.from(registry.querySelectorAll(':scope > details.article-explanation'));
+      const searchRoot = registry.closest('section') || articleMain;
+      items.forEach((item) => {
+        const anchorText = item.dataset.anchorTerm || item.dataset.helpLabel || '';
+        const match = firstTermMatch(searchRoot, anchorText);
+        const fallbackAnchor = registry.previousElementSibling;
+        const anchor = match ? anchorBlockFor(match.node) : fallbackAnchor;
+        if (!anchor) return;
+        const layout = ensureLayout(anchor);
+        layoutSlot(layout).appendChild(item);
+        const helpLabel = item.dataset.helpLabel || anchorText;
+        const category = item.classList.contains('lexical') ? 'lexical' : 'design';
+        const help = makeHelpButton({
+          label: `Explain ${helpLabel}`,
+          controls: [item.id],
+          classes: ['term-help-icon', category]
+        });
+        if (match) appendInlineHelp(match, help);
+        else anchor.appendChild(help);
+      });
+      registry.remove();
+    });
+
+    const explanations = Array.from(document.querySelectorAll('details.article-explanation'));
+    const mathExplanations = explanations.filter((item) => item.classList.contains('math-explanation'));
+    const terminologyExplanations = explanations.filter((item) => item.classList.contains('term-explanation'));
+    const helpButtons = Array.from(document.querySelectorAll('.article-help-icon'));
+    const heading = document.getElementById('article-explanations-heading');
+    const description = document.getElementById('article-explanations-description');
+    const status = document.getElementById('article-explanations-status');
+    const itemOrigins = new Map();
+    const itemAnchors = new Map();
+    explanations.forEach((item) => {
+      const slot = item.closest('.article-explanation-slot');
+      const layout = slot?.closest('.article-explanation-layout');
+      itemOrigins.set(item, slot);
+      itemAnchors.set(item, layout?.querySelector(':scope > .article-explanation-anchor') || null);
+    });
+    const rail = document.createElement('aside');
+    rail.className = 'article-explanation-rail';
+    rail.setAttribute('aria-label', 'Expanded explanations');
+    const railGuide = document.createElement('section');
+    railGuide.className = 'article-explanation-rail-guide';
+    const railGuideHeading = document.createElement('strong');
+    railGuideHeading.textContent = 'Using explanation cards';
+    const railGuideText = document.createElement('p');
+    railGuideText.textContent = 'Cards relevant to the text in view scroll into place automatically. You can also scroll these cards independently. Select an open card to hide it.';
+    const railHideAll = document.createElement('button');
+    railHideAll.type = 'button';
+    railHideAll.className = 'article-explanation-hide-all';
+    railHideAll.textContent = 'Hide all explanations';
+    railGuide.appendChild(railGuideHeading);
+    railGuide.appendChild(railGuideText);
+    railGuide.appendChild(railHideAll);
+    const railStack = document.createElement('div');
+    railStack.className = 'article-explanation-rail-stack';
+    rail.appendChild(railGuide);
+    rail.appendChild(railStack);
+    document.body.appendChild(rail);
+
+    const controlledItems = (help) => (help.getAttribute('aria-controls') || '')
+      .split(/\s+/)
+      .filter(Boolean)
+      .map((id) => document.getElementById(id))
+      .filter(Boolean);
+    const setOpen = (item, open) => {
+      item.open = open;
+    };
+    const layouts = () => Array.from(document.querySelectorAll('.article-explanation-layout'));
+    const arrangeForViewport = () => {
+      if (marginQuery.matches) {
+        explanations.forEach((item) => railStack.appendChild(item));
+      } else {
+        explanations.forEach((item) => itemOrigins.get(item)?.appendChild(item));
+      }
+    };
+    const relevantOpenItem = () => {
+      const viewportCentre = window.innerHeight / 2;
+      let relevant = null;
+      let nearestDistance = Number.POSITIVE_INFINITY;
+      const consideredAnchors = new Set();
+      explanations.forEach((item) => {
+        if (!item.open) return;
+        const anchor = itemAnchors.get(item);
+        if (!anchor || consideredAnchors.has(anchor)) return;
+        consideredAnchors.add(anchor);
+        const rect = anchor.getBoundingClientRect();
+        const distance = Math.abs((rect.top + rect.bottom) / 2 - viewportCentre);
+        if (distance < nearestDistance) {
+          relevant = item;
+          nearestDistance = distance;
+        }
+      });
+      return relevant;
+    };
+    const centreRelevantExplanation = () => {
+      explanations.forEach((item) => item.classList.remove('is-relevant'));
+      if (!marginQuery.matches) return;
+      const relevant = relevantOpenItem();
+      if (!relevant) return;
+      relevant.classList.add('is-relevant');
+      const railRect = rail.getBoundingClientRect();
+      const viewportCentreWithinRail = window.innerHeight / 2 - railRect.top;
+      const targetScroll = relevant.offsetTop + relevant.offsetHeight / 2 - viewportCentreWithinRail;
+      rail.scrollTop = Math.max(0, targetScroll);
+    };
+    let placementFrame = null;
+    const schedulePlacement = () => {
+      if (placementFrame !== null) return;
+      placementFrame = window.requestAnimationFrame(() => {
+        placementFrame = null;
+        centreRelevantExplanation();
+      });
+    };
+    const sync = () => {
+      const openItems = explanations.filter((item) => item.open);
+      const allOpen = explanations.length > 0 && openItems.length === explanations.length;
+      const openMath = mathExplanations.filter((item) => item.open).length;
+      const openTerms = terminologyExplanations.filter((item) => item.open).length;
+
+      helpButtons.forEach((help) => {
+        const targets = controlledItems(help);
+        help.setAttribute('aria-expanded', String(targets.length > 0 && targets.every((item) => item.open)));
+      });
+      layouts().forEach((layout) => {
+        const slot = layoutSlot(layout);
+        const hasOpen = explanations.some((item) => item.open && itemOrigins.get(item) === slot);
+        if (slot) slot.classList.toggle('has-open', hasOpen);
+      });
+      rail.classList.toggle('has-open', openItems.length > 0);
+      document.body.classList.toggle('article-explanations-open', openItems.length > 0);
+      if (articleMain) articleMain.classList.toggle('article-explanations-open', openItems.length > 0);
+      globalButton.setAttribute('aria-pressed', String(allOpen));
+      globalButton.textContent = `${allOpen ? 'Hide' : 'Show'} all help`;
+      if (heading) heading.textContent = 'Reading controls';
+      const bothKinds = mathExplanations.length > 0 && terminologyExplanations.length > 0;
+      const countParts = [];
+      const progressParts = [];
+      if (mathExplanations.length > 0) {
+        countParts.push(`${mathExplanations.length} mathematical item${mathExplanations.length === 1 ? '' : 's'}`);
+        progressParts.push(`${openMath} of ${mathExplanations.length} mathematical item${mathExplanations.length === 1 ? '' : 's'}`);
+      }
+      if (terminologyExplanations.length > 0) {
+        countParts.push(`${terminologyExplanations.length} terminology item${terminologyExplanations.length === 1 ? '' : 's'}`);
+        progressParts.push(`${openTerms} of ${terminologyExplanations.length} terminology item${terminologyExplanations.length === 1 ? '' : 's'}`);
+      }
+      if (description) {
+        const helpInstruction = bothKinds
+          ? 'Use the ? beside a term or equation for optional explanations.'
+          : mathExplanations.length > 0
+            ? 'Use the ? beside an equation for optional explanations.'
+            : 'Use the ? beside a term for an optional definition.';
+        description.textContent = codeDetails.length > 0
+          ? `${helpInstruction} Code details remain inline and independent.`
+          : helpInstruction;
+      }
+      if (status) {
+        status.textContent = openItems.length === 0
+          ? `${countParts.join(' and ')} ${explanations.length === 1 ? 'is' : 'are'} hidden.`
+          : `${progressParts.join(' and ')} shown.`;
+      }
+
+      const openCodeCount = codeDetails.filter((item) => item.open).length;
+      const allCodeOpen = codeDetails.length > 0 && openCodeCount === codeDetails.length;
+      if (codeAction) codeAction.hidden = codeDetails.length === 0;
+      if (codeButton) {
+        codeButton.setAttribute('aria-pressed', String(allCodeOpen));
+        codeButton.textContent = allCodeOpen ? 'Hide all code details' : 'Show all code details';
+      }
+      if (codeStatus) codeStatus.textContent = `${openCodeCount}/${codeDetails.length} code details open.`;
+    };
+
+    globalButton.addEventListener('click', () => {
+      const shouldOpen = !explanations.every((item) => item.open);
+      explanations.forEach((item) => setOpen(item, shouldOpen));
+      sync();
+      schedulePlacement();
+    });
+    if (codeButton) {
+      codeButton.addEventListener('click', () => {
+        const shouldOpen = !codeDetails.every((item) => item.open);
+        codeDetails.forEach((item) => setOpen(item, shouldOpen));
+        sync();
+      });
+    }
+    railHideAll.addEventListener('click', () => {
+      explanations.forEach((item) => setOpen(item, false));
+      sync();
+      schedulePlacement();
+    });
+    helpButtons.forEach((help) => {
+      help.addEventListener('click', () => {
+        const targets = controlledItems(help);
+        const shouldOpen = targets.some((item) => !item.open);
+        targets.forEach((item) => setOpen(item, shouldOpen));
+        sync();
+        schedulePlacement();
+      });
+    });
+    explanations.forEach((item) => {
+      item.addEventListener('click', (event) => {
+        const interactive = event.target instanceof Element && event.target.closest('a,button,input,select,textarea');
+        if (!item.open || interactive) return;
+        event.preventDefault();
+        setOpen(item, false);
+        sync();
+        schedulePlacement();
+      });
+      item.addEventListener('toggle', () => {
+        sync();
+        schedulePlacement();
+      });
+    });
+    codeDetails.forEach((item) => item.addEventListener('toggle', sync));
+    marginQuery.addEventListener('change', () => {
+      arrangeForViewport();
+      sync();
+      schedulePlacement();
+    });
+    window.addEventListener('scroll', schedulePlacement, {passive: true});
+    window.addEventListener('resize', schedulePlacement);
+    if (document.fonts && document.fonts.ready) document.fonts.ready.then(schedulePlacement);
+    window.setTimeout(schedulePlacement, 250);
+    window.setTimeout(schedulePlacement, 1000);
+    globalButton.dataset.initialized = 'true';
+    arrangeForViewport();
+    sync();
+    schedulePlacement();
+  };
+
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', initialise, {once: true});
+  } else {
+    initialise();
+  }
+})();
diff --git a/src/language_learning/vocabulary_estimation/beta_binomial_first_pass.clj b/src/language_learning/vocabulary_estimation/beta_binomial_first_pass.clj
index 8480a3d8..f4d38a7d 100644
--- a/src/language_learning/vocabulary_estimation/beta_binomial_first_pass.clj
+++ b/src/language_learning/vocabulary_estimation/beta_binomial_first_pass.clj
@@ -11,52 +11,33 @@
                   :keywords [:vocabulary-estimation :beta-binomial :posterior-predictive :stratified-sampling]}}}
 
 (ns language-learning.vocabulary-estimation.beta-binomial-first-pass
-  (:require [fastmath.random :as random]
+  (:require [clojure.java.io :as io]
+            [fastmath.random :as random]
             [language-learning.vocabulary-estimation.math-explanations :as math]
             [scicloj.kindly.v4.kind :as kind]))
 
+(defn- resource-text [filename]
+  (let [text (slurp
+              (io/resource
+               (str "language_learning/vocabulary_estimation/" filename)))]
+    (if (= \newline (last text))
+      (subs text 0 (dec (count text)))
+      text)))
+
 ^:kindly/hide-code
 (kind/hiccup
- [:style
-  (str
-   ":root{--ve-accent:#1464b5;--ve-accent-soft:#e5f1fb;--ve-warm:#9a4b00;--ve-warm-soft:#fff0df;--ve-purple:#694aa6;--ve-muted:#4f5b66}"
-   ".quarto-dark{--ve-accent:#73b7ff;--ve-accent-soft:#173653;--ve-warm:#ffc27a;--ve-warm-soft:#4a2d12;--ve-purple:#c5a7ff;--ve-muted:#b9c7d2}"
-   "#title-block-header{padding-top:.75rem}#title-block-header h1{line-height:1.15;overflow-wrap:anywhere}"
-   "mjx-container[display=true]{max-width:100%;overflow-x:auto;overflow-y:hidden}"
-   ".ve-callout{border:1px solid color-mix(in srgb,var(--ve-accent) 45%,var(--bs-border-color,#dee2e6));border-left:4px solid var(--ve-accent);background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-accent) 10%);color:var(--bs-body-color,#212529);padding:1rem 1.15rem;margin:1.4rem 0;border-radius:.35rem}"
-   ".ve-callout.provisional{border-color:color-mix(in srgb,var(--ve-warm) 60%,var(--bs-border-color,#dee2e6));border-left-color:var(--ve-warm);background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-warm) 10%)}"
-   ".ve-callout strong{display:block;margin-bottom:.3rem}.ve-callout p:last-child{margin-bottom:0}"
-   ".ve-grid,.ve-definition-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,15rem),1fr));gap:.75rem;margin:1.25rem 0}"
-   ".ve-card,.ve-definition{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.5rem;padding:.85rem;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529);overflow-wrap:anywhere}"
-   ".ve-card h3{font-size:1rem;margin-top:0}.ve-definition dt{font-weight:800;color:var(--ve-accent)}.ve-definition dd{margin:.25rem 0 0}"
-   ".ve-table-wrap{max-width:100%;overflow-x:auto;margin:1.25rem 0}.ve-table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums}"
-   ".ve-table th,.ve-table td{padding:.55rem .7rem;border-bottom:1px solid var(--bs-border-color,#dee2e6);text-align:right;white-space:nowrap}.ve-table th:first-child,.ve-table td:first-child{text-align:left}.ve-table thead th{border-bottom:2px solid var(--bs-border-color,#adb5bd)}"
-   ".ve-figure{margin:1.5rem 0;padding:1rem;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.5rem;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-figure svg{display:block;width:100%;height:auto}"
-   ".ve-caption,.ve-note{font-size:.9rem;color:var(--ve-muted);margin:.75rem 0 0}.ve-simulator{margin:1.5rem 0}"
-   ".ve-reading-guide{border-left:4px solid var(--ve-accent);padding:.2rem 0 .2rem 1rem;margin:1rem 0}.ve-reading-guide h3{font-size:1rem;margin:.1rem 0 .35rem}.ve-reading-guide ul{margin-bottom:.2rem}"
-   ".ve-hierarchy{display:grid;grid-template-columns:minmax(8rem,.7fr) auto minmax(0,1.5fr);gap:.7rem;align-items:center}.ve-hierarchy-node{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.7rem;text-align:center;background:var(--bs-body-bg,#fff);overflow-wrap:anywhere}.ve-hierarchy-node strong{display:block;color:var(--ve-accent)}"
-   ".ve-hierarchy-arrow{font-size:1.5rem;color:var(--ve-accent);font-weight:800}.ve-form-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.5rem}.ve-sense-gap{grid-column:1/-1;border:2px dashed var(--ve-warm);border-radius:.45rem;padding:.65rem;text-align:center;color:var(--bs-body-color,#212529);background:color-mix(in srgb,var(--bs-body-bg,#fff) 92%,var(--ve-warm) 8%)}"
-   ".ve-sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}"
-   "@media(max-width:767px){.ve-hierarchy{grid-template-columns:minmax(0,1fr)}.ve-hierarchy-arrow{transform:rotate(90deg);text-align:center}.ve-form-list{grid-template-columns:minmax(0,1fr)}}"
-   "@media(max-width:575px){.ve-table th,.ve-table td{padding:.45rem}.ve-figure{padding:.65rem}}")])
+ [:style (resource-text "beta_binomial_first_pass_base.css")])
 
 ^:kindly/hide-code
 (math/styles)
 
 ^:kindly/hide-code
 (kind/hiccup
- [:style
-  (str
-   ".ve-round-shell,.ve-stop-shell{min-width:0;border:1px solid var(--bs-border-color,#ced4da);border-radius:.65rem;padding:clamp(.8rem,3vw,1.3rem);background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}"
-   ".ve-round-shell h3,.ve-stop-shell h3{margin-top:0}.ve-round-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:.55rem;margin:1rem 0}.ve-round-card{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.65rem;background:color-mix(in srgb,var(--bs-body-bg,#fff) 94%,var(--ve-accent) 6%);overflow-wrap:anywhere}.ve-round-card strong,.ve-round-card span,.ve-round-card small{display:block}.ve-round-card small{color:var(--ve-muted);margin-top:.25rem}.ve-round-progress{width:100%;height:.55rem;accent-color:var(--ve-accent)}.ve-round-status{min-height:2.8rem;font-variant-numeric:tabular-nums}"
-   ".ve-stop-banner{display:flex;align-items:baseline;gap:.35rem;flex-wrap:wrap;border-left:4px solid var(--ve-accent);border-radius:.35rem;padding:.65rem .8rem;margin:.8rem 0;background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-accent) 10%)}.ve-stop-banner.is-counterfactual{border-left-color:var(--ve-warm);background:color-mix(in srgb,var(--bs-body-bg,#fff) 90%,var(--ve-warm) 10%)}"
-   ".ve-stop-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,14rem),1fr));gap:.8rem;margin:1rem 0}.ve-stop-field{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.65rem}.ve-stop-field>div{display:flex;justify-content:space-between;align-items:baseline;gap:.5rem}.ve-stop-field label{font-weight:700}.ve-stop-field output{font-variant-numeric:tabular-nums;color:var(--ve-muted);text-align:right}.ve-stop-field input{width:100%;accent-color:var(--ve-accent)}.ve-stop-result{border:1px solid var(--bs-border-color,#dee2e6);border-radius:.45rem;padding:.75rem;margin:1rem 0}.ve-stop-result ul{margin:.5rem 0 0}.ve-sampling-button:disabled{opacity:.5;cursor:not-allowed}.ve-stop-field input:focus-visible{outline:3px solid color-mix(in srgb,var(--ve-accent) 50%,transparent);outline-offset:3px}"
-   "@media(max-width:767px){.ve-round-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:400px){.ve-round-grid{grid-template-columns:minmax(0,1fr)}}")])
+ [:style (resource-text "beta_binomial_first_pass_round.css")])
 
 ^:kindly/hide-code
 (kind/hiccup
- [:style
-  ".series-toc{min-width:0;border:1px solid var(--bs-border-color,#ced4da);border-radius:.6rem;padding:clamp(.85rem,3vw,1.2rem);margin:0 0 1.4rem;background:var(--bs-body-bg,#fff)}.series-toc h2{font-size:1.2rem;margin:0 0 .55rem}.series-toc p{margin:0 0 .7rem}.series-toc ol{margin:0;padding-left:1.45rem}.series-toc li{padding:.18rem .45rem}.series-status{display:inline-block;margin-left:.35rem;font-size:.7rem;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--ve-muted)}.series-current{margin:.35rem 0 .35rem -.7rem;border-left:4px solid var(--ve-accent);border-radius:.4rem;padding:.6rem .75rem!important;background:color-mix(in srgb,var(--bs-body-bg,#fff) 84%,var(--ve-accent) 16%);box-shadow:inset 0 0 0 1px color-mix(in srgb,var(--ve-accent) 35%,transparent);font-weight:700}.series-current>a{color:var(--ve-accent)}.series-current .series-status{border-radius:999px;padding:.18rem .48rem;background:var(--ve-accent);color:#fff}.quarto-dark .series-current .series-status{color:#10212b}"])
+ [:style (resource-text "beta_binomial_first_pass_series.css")])
 
 ^:kindly/hide-code
 (kind/hiccup
@@ -665,8 +646,7 @@
 
 ^:kindly/hide-code
 (kind/hiccup
- [:style
-  ".ve-posterior-sampler{border:1px solid var(--bs-border-color,#ced4da);border-radius:.65rem;padding:clamp(.8rem,3vw,1.3rem);min-width:0;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-sampling-intro{max-width:50rem}.ve-sampling-controls{display:flex;align-items:end;justify-content:space-between;gap:1rem;flex-wrap:wrap;margin:1rem 0}.ve-rate-fieldset{border:0;padding:0;margin:0;min-width:0}.ve-rate-fieldset legend{font-size:.85rem;font-weight:700;margin-bottom:.4rem}.ve-button-row{display:flex;gap:.5rem;flex-wrap:wrap}.ve-sampling-button{border:1px solid var(--bs-border-color,#6c757d);border-radius:.35rem;padding:.55rem .85rem;font-weight:600;cursor:pointer;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-sampling-button[aria-pressed=true],.ve-sampling-button.ve-primary{border-color:#1464b5;background:#1464b5;color:#fff}.quarto-dark .ve-sampling-button[aria-pressed=true],.quarto-dark .ve-sampling-button.ve-primary{border-color:#73b7ff;background:#73b7ff;color:#10212b}.ve-sampling-button:focus-visible{outline:3px solid color-mix(in srgb,var(--ve-accent) 45%,transparent);outline-offset:2px}.ve-sampling-progress{width:100%;height:.55rem;accent-color:var(--ve-accent)}.ve-sampling-grid{display:grid;grid-template-columns:minmax(0,1fr);gap:1rem;margin-top:1rem}.ve-sample-panel{min-width:0;border:1px solid var(--bs-border-color,#dee2e6);border-radius:.5rem;padding:clamp(.65rem,2vw,1rem);margin:0;background:var(--bs-body-bg,#fff);color:var(--bs-body-color,#212529)}.ve-sample-panel h4{font-size:1rem;margin:0 0 .25rem}.ve-sample-panel svg{display:block;width:100%;height:auto}.ve-sample-stat{font-variant-numeric:tabular-nums;margin:.2rem 0 .65rem}.ve-sample-note{font-size:.85rem;color:var(--ve-muted);margin:.5rem 0 0}.ve-empty-sample{display:grid;place-items:center;min-height:13rem;border:1px dashed var(--bs-border-color,#adb5bd);border-radius:.35rem;color:var(--ve-muted);text-align:center;padding:1rem}.ve-sampling-status{font-variant-numeric:tabular-nums;margin:.4rem 0}.ve-dot{fill:var(--ve-accent);fill-opacity:.72}.ve-dot-latest{fill:var(--ve-warm);stroke:var(--bs-body-bg,#fff);stroke-width:1.5}.ve-sample-axis{stroke:currentColor;stroke-opacity:.45}.ve-sample-guide{stroke:currentColor;stroke-opacity:.1}.ve-latest-line{stroke:var(--ve-accent);stroke-width:5;stroke-linecap:round}.ve-latest-dot{fill:var(--ve-warm);stroke:var(--bs-body-bg,#fff);stroke-width:2}.ve-draw-breakdown{width:100%;border-collapse:collapse;font-size:.82rem;font-variant-numeric:tabular-nums;margin-top:.75rem}.ve-draw-breakdown th,.ve-draw-breakdown td{padding:.35rem .45rem;border-bottom:1px solid var(--bs-border-color,#dee2e6);text-align:right;white-space:nowrap}.ve-draw-breakdown th:first-child{text-align:left}.ve-draw-breakdown-wrap{max-width:100%;overflow-x:auto}@media(max-width:575px){.ve-sampling-controls{align-items:stretch}.ve-sampling-controls>.ve-button-row{width:100%}.ve-sampling-controls>.ve-button-row .ve-sampling-button{flex:1}.ve-sampling-button{padding:.55rem .7rem}}"])
+ [:style (resource-text "beta_binomial_first_pass_sampler.css")])
 
 ^:kindly/hide-code
 (kind/hiccup
diff --git a/src/language_learning/vocabulary_estimation/math_explanations.clj b/src/language_learning/vocabulary_estimation/math_explanations.clj
index ea16a3ef..6d570eae 100644
--- a/src/language_learning/vocabulary_estimation/math_explanations.clj
+++ b/src/language_learning/vocabulary_estimation/math_explanations.clj
@@ -1,5 +1,6 @@
 (ns language-learning.vocabulary-estimation.math-explanations
-  (:require [scicloj.kindly.v4.kind :as kind]))
+  (:require [clojure.java.io :as io]
+            [scicloj.kindly.v4.kind :as kind]))
 
 (defn styles []
   (kind/hiccup
@@ -78,356 +79,12 @@
      "@media(max-width:767px){.article-explanations-toolbar{grid-template-columns:minmax(0,1fr);align-items:stretch}.article-explanations-toggle,.article-code-toggle{width:100%}.article-reading-action{width:100%}}")]))
 
 (def ^:private explanation-controls-script
-  "(() => {
-  const initialise = () => {
-    const globalButton = document.getElementById('article-explanations-toggle');
-    if (!globalButton || globalButton.dataset.initialized === 'true') return;
-
-    const articleMain = document.getElementById('quarto-document-content') || document.querySelector('main');
-    const marginQuery = window.matchMedia('(min-width: 1280px)');
-    const mathRegistries = Array.from(document.querySelectorAll('.math-explanation-registry'));
-    const termRegistries = Array.from(document.querySelectorAll('.term-explanation-registry'));
-    const codeDetails = Array.from(document.querySelectorAll('details.article-code-detail'));
-    const codeAction = document.getElementById('article-code-action');
-    const codeButton = document.getElementById('article-code-toggle');
-    const codeStatus = document.getElementById('article-code-status');
-
-    const makeHelpButton = ({label, controls, classes = []}) => {
-      const help = document.createElement('button');
-      help.type = 'button';
-      help.className = ['article-help-icon', ...classes].join(' ');
-      help.textContent = '?';
-      help.setAttribute('aria-label', label);
-      help.setAttribute('title', label);
-      help.setAttribute('aria-controls', controls.join(' '));
-      help.setAttribute('aria-expanded', 'false');
-      return help;
-    };
-
-    const ensureLayout = (anchor) => {
-      const existing = anchor.closest('.article-explanation-layout');
-      if (existing && existing.querySelector(':scope > .article-explanation-anchor') === anchor) {
-        return existing;
-      }
-      const layout = document.createElement('div');
-      layout.className = 'article-explanation-layout';
-      const slot = document.createElement('div');
-      slot.className = 'article-explanation-slot';
-      anchor.classList.add('article-explanation-anchor');
-      anchor.parentElement.insertBefore(layout, anchor);
-      layout.appendChild(anchor);
-      layout.appendChild(slot);
-      return layout;
-    };
-
-    const layoutSlot = (layout) => layout.querySelector(':scope > .article-explanation-slot');
-    const containsDisplayEquation = (node) => Boolean(
-      node && node.querySelector('span.math.display, mjx-container[display=true]')
-    );
-    const precedingEquation = (registry) => {
-      let cursor = registry;
-      for (let depth = 0; cursor && cursor.parentElement && depth < 4; depth += 1) {
-        let candidate = cursor.previousElementSibling;
-        while (candidate) {
-          if (containsDisplayEquation(candidate)) return candidate;
-          candidate = candidate.previousElementSibling;
-        }
-        if (cursor.parentElement.matches('section')) break;
-        cursor = cursor.parentElement;
-      }
-      return null;
-    };
-
-    mathRegistries.forEach((registry, registryIndex) => {
-      const items = Array.from(registry.querySelectorAll(':scope > details.article-explanation'));
-      const anchor = precedingEquation(registry);
-      if (!anchor || items.length === 0) return;
-      const accentClass = `accent-${(registryIndex % 6) + 1}`;
-      const layout = ensureLayout(anchor);
-      layout.classList.add('equation-explanation-layout');
-      const slot = layoutSlot(layout);
-      items.forEach((item) => {
-        item.classList.add(accentClass);
-        slot.appendChild(item);
-      });
-      anchor.classList.add('equation-help-anchor');
-      const title = registry.dataset.explanationTitle || 'this equation';
-      const help = makeHelpButton({
-        label: `Explain ${title}`,
-        controls: items.map((item) => item.id),
-        classes: ['equation-help-icon', accentClass]
-      });
-      anchor.appendChild(help);
-      registry.remove();
-    });
-
-    const excludedTextNode = (node) => Boolean(node.parentElement && node.parentElement.closest(
-      'script,style,pre,code,svg,details,.article-explanations-toolbar,.article-explanation-registry,.article-help-icon'
-    ));
-    const normaliseTerm = (text) => text.toLocaleLowerCase().replace(/[‐‑‒–—]/g, '-');
-    const isBoundary = (character) => !character || !/[A-Za-z0-9‐‑‒–—-]/.test(character);
-    const firstTermMatch = (root, text) => {
-      const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT);
-      const needle = normaliseTerm(text);
-      let node;
-      while ((node = walker.nextNode())) {
-        if (excludedTextNode(node)) continue;
-        const haystack = normaliseTerm(node.nodeValue || '');
-        let index = haystack.indexOf(needle);
-        while (index >= 0) {
-          const afterIndex = index + needle.length;
-          const plural = haystack[afterIndex] === 's' && isBoundary(haystack[afterIndex + 1]);
-          if (isBoundary(haystack[index - 1]) && (isBoundary(haystack[afterIndex]) || plural)) {
-            return {node, index, length: needle.length + (plural ? 1 : 0)};
-          }
-          index = haystack.indexOf(needle, index + 1);
-        }
-      }
-      return null;
-    };
-    const anchorBlockFor = (node) => node.parentElement?.closest('p,blockquote,li,figcaption,h2,h3,h4') || node.parentElement;
-    const appendInlineHelp = (match, help) => {
-      const after = match.node.splitText(match.index + match.length);
-      after.parentNode.insertBefore(help, after);
-    };
-
-    termRegistries.forEach((registry) => {
-      const items = Array.from(registry.querySelectorAll(':scope > details.article-explanation'));
-      const searchRoot = registry.closest('section') || articleMain;
-      items.forEach((item) => {
-        const anchorText = item.dataset.anchorTerm || item.dataset.helpLabel || '';
-        const match = firstTermMatch(searchRoot, anchorText);
-        const fallbackAnchor = registry.previousElementSibling;
-        const anchor = match ? anchorBlockFor(match.node) : fallbackAnchor;
-        if (!anchor) return;
-        const layout = ensureLayout(anchor);
-        layoutSlot(layout).appendChild(item);
-        const helpLabel = item.dataset.helpLabel || anchorText;
-        const category = item.classList.contains('lexical') ? 'lexical' : 'design';
-        const help = makeHelpButton({
-          label: `Explain ${helpLabel}`,
-          controls: [item.id],
-          classes: ['term-help-icon', category]
-        });
-        if (match) appendInlineHelp(match, help);
-        else anchor.appendChild(help);
-      });
-      registry.remove();
-    });
-
-    const explanations = Array.from(document.querySelectorAll('details.article-explanation'));
-    const mathExplanations = explanations.filter((item) => item.classList.contains('math-explanation'));
-    const terminologyExplanations = explanations.filter((item) => item.classList.contains('term-explanation'));
-    const helpButtons = Array.from(document.querySelectorAll('.article-help-icon'));
-    const heading = document.getElementById('article-explanations-heading');
-    const description = document.getElementById('article-explanations-description');
-    const status = document.getElementById('article-explanations-status');
-    const itemOrigins = new Map();
-    const itemAnchors = new Map();
-    explanations.forEach((item) => {
-      const slot = item.closest('.article-explanation-slot');
-      const layout = slot?.closest('.article-explanation-layout');
-      itemOrigins.set(item, slot);
-      itemAnchors.set(item, layout?.querySelector(':scope > .article-explanation-anchor') || null);
-    });
-    const rail = document.createElement('aside');
-    rail.className = 'article-explanation-rail';
-    rail.setAttribute('aria-label', 'Expanded explanations');
-    const railGuide = document.createElement('section');
-    railGuide.className = 'article-explanation-rail-guide';
-    const railGuideHeading = document.createElement('strong');
-    railGuideHeading.textContent = 'Using explanation cards';
-    const railGuideText = document.createElement('p');
-    railGuideText.textContent = 'Cards relevant to the text in view scroll into place automatically. You can also scroll these cards independently. Select an open card to hide it.';
-    const railHideAll = document.createElement('button');
-    railHideAll.type = 'button';
-    railHideAll.className = 'article-explanation-hide-all';
-    railHideAll.textContent = 'Hide all explanations';
-    railGuide.appendChild(railGuideHeading);
-    railGuide.appendChild(railGuideText);
-    railGuide.appendChild(railHideAll);
-    const railStack = document.createElement('div');
-    railStack.className = 'article-explanation-rail-stack';
-    rail.appendChild(railGuide);
-    rail.appendChild(railStack);
-    document.body.appendChild(rail);
-
-    const controlledItems = (help) => (help.getAttribute('aria-controls') || '')
-      .split(/\\s+/)
-      .filter(Boolean)
-      .map((id) => document.getElementById(id))
-      .filter(Boolean);
-    const setOpen = (item, open) => {
-      item.open = open;
-    };
-    const layouts = () => Array.from(document.querySelectorAll('.article-explanation-layout'));
-    const arrangeForViewport = () => {
-      if (marginQuery.matches) {
-        explanations.forEach((item) => railStack.appendChild(item));
-      } else {
-        explanations.forEach((item) => itemOrigins.get(item)?.appendChild(item));
-      }
-    };
-    const relevantOpenItem = () => {
-      const viewportCentre = window.innerHeight / 2;
-      let relevant = null;
-      let nearestDistance = Number.POSITIVE_INFINITY;
-      const consideredAnchors = new Set();
-      explanations.forEach((item) => {
-        if (!item.open) return;
-        const anchor = itemAnchors.get(item);
-        if (!anchor || consideredAnchors.has(anchor)) return;
-        consideredAnchors.add(anchor);
-        const rect = anchor.getBoundingClientRect();
-        const distance = Math.abs((rect.top + rect.bottom) / 2 - viewportCentre);
-        if (distance < nearestDistance) {
-          relevant = item;
-          nearestDistance = distance;
-        }
-      });
-      return relevant;
-    };
-    const centreRelevantExplanation = () => {
-      explanations.forEach((item) => item.classList.remove('is-relevant'));
-      if (!marginQuery.matches) return;
-      const relevant = relevantOpenItem();
-      if (!relevant) return;
-      relevant.classList.add('is-relevant');
-      const railRect = rail.getBoundingClientRect();
-      const viewportCentreWithinRail = window.innerHeight / 2 - railRect.top;
-      const targetScroll = relevant.offsetTop + relevant.offsetHeight / 2 - viewportCentreWithinRail;
-      rail.scrollTop = Math.max(0, targetScroll);
-    };
-    let placementFrame = null;
-    const schedulePlacement = () => {
-      if (placementFrame !== null) return;
-      placementFrame = window.requestAnimationFrame(() => {
-        placementFrame = null;
-        centreRelevantExplanation();
-      });
-    };
-    const sync = () => {
-      const openItems = explanations.filter((item) => item.open);
-      const allOpen = explanations.length > 0 && openItems.length === explanations.length;
-      const openMath = mathExplanations.filter((item) => item.open).length;
-      const openTerms = terminologyExplanations.filter((item) => item.open).length;
-
-      helpButtons.forEach((help) => {
-        const targets = controlledItems(help);
-        help.setAttribute('aria-expanded', String(targets.length > 0 && targets.every((item) => item.open)));
-      });
-      layouts().forEach((layout) => {
-        const slot = layoutSlot(layout);
-        const hasOpen = explanations.some((item) => item.open && itemOrigins.get(item) === slot);
-        if (slot) slot.classList.toggle('has-open', hasOpen);
-      });
-      rail.classList.toggle('has-open', openItems.length > 0);
-      document.body.classList.toggle('article-explanations-open', openItems.length > 0);
-      if (articleMain) articleMain.classList.toggle('article-explanations-open', openItems.length > 0);
-      globalButton.setAttribute('aria-pressed', String(allOpen));
-      globalButton.textContent = `${allOpen ? 'Hide' : 'Show'} all help`;
-      if (heading) heading.textContent = 'Reading controls';
-      const bothKinds = mathExplanations.length > 0 && terminologyExplanations.length > 0;
-      const countParts = [];
-      const progressParts = [];
-      if (mathExplanations.length > 0) {
-        countParts.push(`${mathExplanations.length} mathematical item${mathExplanations.length === 1 ? '' : 's'}`);
-        progressParts.push(`${openMath} of ${mathExplanations.length} mathematical item${mathExplanations.length === 1 ? '' : 's'}`);
-      }
-      if (terminologyExplanations.length > 0) {
-        countParts.push(`${terminologyExplanations.length} terminology item${terminologyExplanations.length === 1 ? '' : 's'}`);
-        progressParts.push(`${openTerms} of ${terminologyExplanations.length} terminology item${terminologyExplanations.length === 1 ? '' : 's'}`);
-      }
-      if (description) {
-        const helpInstruction = bothKinds
-          ? 'Use the ? beside a term or equation for optional explanations.'
-          : mathExplanations.length > 0
-            ? 'Use the ? beside an equation for optional explanations.'
-            : 'Use the ? beside a term for an optional definition.';
-        description.textContent = codeDetails.length > 0
-          ? `${helpInstruction} Code details remain inline and independent.`
-          : helpInstruction;
-      }
-      if (status) {
-        status.textContent = openItems.length === 0
-          ? `${countParts.join(' and ')} ${explanations.length === 1 ? 'is' : 'are'} hidden.`
-          : `${progressParts.join(' and ')} shown.`;
-      }
-
-      const openCodeCount = codeDetails.filter((item) => item.open).length;
-      const allCodeOpen = codeDetails.length > 0 && openCodeCount === codeDetails.length;
-      if (codeAction) codeAction.hidden = codeDetails.length === 0;
-      if (codeButton) {
-        codeButton.setAttribute('aria-pressed', String(allCodeOpen));
-        codeButton.textContent = allCodeOpen ? 'Hide all code details' : 'Show all code details';
-      }
-      if (codeStatus) codeStatus.textContent = `${openCodeCount}/${codeDetails.length} code details open.`;
-    };
-
-    globalButton.addEventListener('click', () => {
-      const shouldOpen = !explanations.every((item) => item.open);
-      explanations.forEach((item) => setOpen(item, shouldOpen));
-      sync();
-      schedulePlacement();
-    });
-    if (codeButton) {
-      codeButton.addEventListener('click', () => {
-        const shouldOpen = !codeDetails.every((item) => item.open);
-        codeDetails.forEach((item) => setOpen(item, shouldOpen));
-        sync();
-      });
-    }
-    railHideAll.addEventListener('click', () => {
-      explanations.forEach((item) => setOpen(item, false));
-      sync();
-      schedulePlacement();
-    });
-    helpButtons.forEach((help) => {
-      help.addEventListener('click', () => {
-        const targets = controlledItems(help);
-        const shouldOpen = targets.some((item) => !item.open);
-        targets.forEach((item) => setOpen(item, shouldOpen));
-        sync();
-        schedulePlacement();
-      });
-    });
-    explanations.forEach((item) => {
-      item.addEventListener('click', (event) => {
-        const interactive = event.target instanceof Element && event.target.closest('a,button,input,select,textarea');
-        if (!item.open || interactive) return;
-        event.preventDefault();
-        setOpen(item, false);
-        sync();
-        schedulePlacement();
-      });
-      item.addEventListener('toggle', () => {
-        sync();
-        schedulePlacement();
-      });
-    });
-    codeDetails.forEach((item) => item.addEventListener('toggle', sync));
-    marginQuery.addEventListener('change', () => {
-      arrangeForViewport();
-      sync();
-      schedulePlacement();
-    });
-    window.addEventListener('scroll', schedulePlacement, {passive: true});
-    window.addEventListener('resize', schedulePlacement);
-    if (document.fonts && document.fonts.ready) document.fonts.ready.then(schedulePlacement);
-    window.setTimeout(schedulePlacement, 250);
-    window.setTimeout(schedulePlacement, 1000);
-    globalButton.dataset.initialized = 'true';
-    arrangeForViewport();
-    sync();
-    schedulePlacement();
-  };
-
-  if (document.readyState === 'loading') {
-    document.addEventListener('DOMContentLoaded', initialise, {once: true});
-  } else {
-    initialise();
-  }
-})();")
+  (let [script (slurp
+                (io/resource
+                 "language_learning/vocabulary_estimation/math_explanations.js"))]
+    (if (= \newline (last script))
+      (subs script 0 (dec (count script)))
+      script)))
 
 (defn global-controls []
   (kind/hiccup