diff --git a/plots/acf-pacf/implementations/javascript/chartjs.js b/plots/acf-pacf/implementations/javascript/chartjs.js
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+// anyplot.ai
+// acf-pacf: Autocorrelation and Partial Autocorrelation (ACF/PACF) Plot
+// Library: chartjs 4.4.7 | JavaScript 22.22.3
+// Quality: 84/100 | Created: 2026-06-10
+
+//# anyplot-orientation: landscape
+
+const t = window.ANYPLOT_TOKENS;
+
+// Deterministic LCG for reproducible pseudo-random numbers (no seeded RNG in browser)
+let _seed = 42;
+function lcgRand() {
+  _seed = (Math.imul(1664525, _seed) + 1013904223) >>> 0;
+  return _seed / 4294967296;
+}
+function stdNormal() {
+  const u1 = lcgRand() || 1e-10;
+  return Math.sqrt(-2 * Math.log(u1)) * Math.cos(2 * Math.PI * lcgRand());
+}
+
+// AR(2) process: x_t = 0.7*x_{t-1} + 0.2*x_{t-2} + ε_t
+// Classic diagnostic: ACF decays exponentially; PACF cuts off exactly after lag 2
+const N = 240;
+const series = [stdNormal(), stdNormal()];
+for (let i = 2; i < N; i++) {
+  series.push(0.7 * series[i - 1] + 0.2 * series[i - 2] + stdNormal());
+}
+
+// Sample ACF at lags 0..maxLag (biased estimator, consistent with standard practice)
+function computeACF(s, maxLag) {
+  const n = s.length;
+  const mean = s.reduce((a, b) => a + b, 0) / n;
+  const variance = s.reduce((a, b) => a + (b - mean) ** 2, 0) / n;
+  return Array.from({ length: maxLag + 1 }, (_, k) => {
+    const cov = s
+      .slice(0, n - k)
+      .reduce((sum, v, i) => sum + (v - mean) * (s[i + k] - mean), 0);
+    return cov / (n * variance);
+  });
+}
+
+// PACF at lags 1..maxLag via Levinson-Durbin recursion
+function computePACF(acfVals, maxLag) {
+  const result = [acfVals[1]];
+  let phi = [acfVals[1]];
+  for (let k = 2; k <= maxLag; k++) {
+    let num = acfVals[k],
+      den = 1;
+    for (let j = 0; j < k - 1; j++) {
+      num -= phi[j] * acfVals[k - j - 1];
+      den -= phi[j] * acfVals[j + 1];
+    }
+    const phikk = Math.abs(den) < 1e-12 ? 0 : num / den;
+    result.push(phikk);
+    phi = Array.from({ length: k }, (_, j) =>
+      j === k - 1 ? phikk : phi[j] - phikk * phi[k - 2 - j]
+    );
+  }
+  return result;
+}
+
+const MAX_LAG = 30;
+const acfData = computeACF(series, MAX_LAG); // lags 0..30 (lag 0 = 1.0)
+const pacfData = computePACF(acfData, MAX_LAG); // lags 1..30
+const CI = 1.96 / Math.sqrt(N); // 95% confidence bound: ±1.96/√N
+
+// Brand green for positive correlations, matte red for negative
+const stemColor = (v) => (v >= 0 ? t.palette[0] : t.palette[4]);
+
+// DOM: flex column with overall title + two equal-height chart panes
+const container = document.getElementById("container");
+container.style.cssText = `
+  display: flex; flex-direction: column; gap: 8px;
+  background: ${t.pageBg}; padding: 30px 64px 26px;
+  box-sizing: border-box;
+`;
+
+const titleEl = document.createElement("div");
+titleEl.textContent = "acf-pacf · javascript · chartjs · anyplot.ai";
+titleEl.style.cssText = `
+  color: ${t.ink}; font: 700 22px/1.3 system-ui, -apple-system, sans-serif;
+  text-align: center; flex-shrink: 0;
+`;
+container.appendChild(titleEl);
+
+function makePane() {
+  const wrap = document.createElement("div");
+  wrap.style.cssText = "flex: 1; position: relative; min-height: 0;";
+  const canvas = document.createElement("canvas");
+  wrap.appendChild(canvas);
+  container.appendChild(wrap);
+  return canvas;
+}
+const acfCanvas = makePane();
+const pacfCanvas = makePane();
+
+// Horizontal dashed CI line dataset (same constant value across all lags)
+function ciLine(n, val, label) {
+  return {
+    type: "line",
+    label,
+    data: new Array(n).fill(val),
+    borderColor: t.inkSoft,
+    borderDash: [8, 5],
+    borderWidth: 1.5,
+    pointRadius: 0,
+    fill: false,
+    tension: 0,
+  };
+}
+
+// Highlight zero baseline gridline for clear significance reference
+const zeroGridColor = (ctx) => (ctx.tick?.value === 0 ? t.inkSoft : t.grid);
+
+// Shared y-axis config for both subplots
+function yAxis(label) {
+  return {
+    ticks: { color: t.inkSoft, font: { size: 14 }, maxTicksLimit: 7 },
+    grid: { color: zeroGridColor },
+    border: { display: false },
+    title: {
+      display: true,
+      text: label,
+      color: t.ink,
+      font: { size: 14, weight: "600" },
+    },
+    suggestedMin: -1.1,
+    suggestedMax: 1.15,
+  };
+}
+
+// Legend: show only the "95% CI" dashed line entry
+const legendConfig = {
+  labels: {
+    color: t.inkSoft,
+    font: { size: 13 },
+    filter: (item) => item.text === "95% CI",
+    boxWidth: 24,
+  },
+};
+
+// ACF chart — lags 0..30 (lag 0 = 1.0 always included per spec)
+new Chart(acfCanvas, {
+  type: "bar",
+  data: {
+    labels: Array.from({ length: MAX_LAG + 1 }, (_, i) => i),
+    datasets: [
+      {
+        label: "ACF",
+        data: acfData,
+        backgroundColor: acfData.map(stemColor),
+        borderWidth: 0,
+        barThickness: 7,
+      },
+      ciLine(MAX_LAG + 1, CI, "95% CI"),
+      ciLine(MAX_LAG + 1, -CI, ""),
+    ],
+  },
+  options: {
+    responsive: true,
+    maintainAspectRatio: false,
+    animation: false,
+    plugins: {
+      title: { display: false },
+      legend: { display: false },
+    },
+    scales: {
+      x: {
+        ticks: { color: t.inkSoft, font: { size: 14 }, maxTicksLimit: 16 },
+        grid: { display: false },
+        border: { display: false },
+        title: { display: false }, // "Lag" label shown on bottom chart only
+      },
+      y: yAxis("ACF"),
+    },
+  },
+});
+
+// PACF chart — lags 1..30 (no lag 0 per spec)
+new Chart(pacfCanvas, {
+  type: "bar",
+  data: {
+    labels: Array.from({ length: MAX_LAG }, (_, i) => i + 1),
+    datasets: [
+      {
+        label: "PACF",
+        data: pacfData,
+        backgroundColor: pacfData.map(stemColor),
+        borderWidth: 0,
+        barThickness: 7,
+      },
+      ciLine(MAX_LAG, CI, "95% CI"),
+      ciLine(MAX_LAG, -CI, ""),
+    ],
+  },
+  options: {
+    responsive: true,
+    maintainAspectRatio: false,
+    animation: false,
+    plugins: {
+      title: { display: false },
+      legend: legendConfig,
+    },
+    scales: {
+      x: {
+        ticks: { color: t.inkSoft, font: { size: 14 } },
+        grid: { display: false },
+        border: { display: false },
+        title: {
+          display: true,
+          text: "Lag",
+          color: t.ink,
+          font: { size: 14, weight: "600" },
+        },
+      },
+      y: yAxis("PACF"),
+    },
+  },
+});
diff --git a/plots/acf-pacf/metadata/javascript/chartjs.yaml b/plots/acf-pacf/metadata/javascript/chartjs.yaml
new file mode 100644
index 0000000000..3cd7a7fa72
--- /dev/null
+++ b/plots/acf-pacf/metadata/javascript/chartjs.yaml
@@ -0,0 +1,257 @@
+library: chartjs
+language: javascript
+specification_id: acf-pacf
+created: '2026-06-10T02:03:27Z'
+updated: '2026-06-10T02:27:20Z'
+generated_by: claude-sonnet
+workflow_run: 27247770776
+issue: 4663
+language_version: 22.22.3
+library_version: 4.4.7
+preview_url_light: https://storage.googleapis.com/anyplot-images/plots/acf-pacf/javascript/chartjs/plot-light.png
+preview_url_dark: https://storage.googleapis.com/anyplot-images/plots/acf-pacf/javascript/chartjs/plot-dark.png
+preview_html_light: https://storage.googleapis.com/anyplot-images/plots/acf-pacf/javascript/chartjs/plot-light.html
+preview_html_dark: https://storage.googleapis.com/anyplot-images/plots/acf-pacf/javascript/chartjs/plot-dark.html
+quality_score: 84
+review:
+  strengths:
+  - 'Textbook AR(2) dataset demonstrates all key ACF/PACF diagnostic properties: exponential
+    decay, PACF cutoff at model order, lag-0 = 1.0, positive and negative correlations'
+  - Semantic green/red color coding (Imprint palette) for positive/negative correlations
+    is statistically correct and visually clear
+  - Mathematically sound Levinson-Durbin PACF computation and biased ACF estimator
+    — correct statistical implementation
+  - Dual-canvas flex layout cleanly solves Chart.js's lack of native subplot support
+  - All theme tokens correctly applied; both light and dark renders pass theme-readability
+    checks with no chrome failures
+  - Scriptable grid color callback (zero-line highlight via zeroGridColor) is an elegant
+    Chart.js-idiomatic touch
+  - Fixed LCG seed (seed=42) with Box-Muller transform ensures fully deterministic
+    output
+  weaknesses:
+  - 'ACF x-axis uses maxTicksLimit:16 (even lags: 0, 2, 4…) while PACF shows all 30
+    lags — inconsistent tick density between panels makes the shared x-axis harder
+    to read as a unified scale; apply same maxTicksLimit to both x-axes'
+  - Y-axis renders to approximately ±1.5 in practice (Chart.js padding beyond suggestedMin/Max),
+    creating unused vertical space since ACF is all-positive and most PACF values
+    cluster within ±0.15 for lags > 2; tighten suggestedMin to ~-0.4 and suggestedMax
+    to ~1.1
+  - No real-world domain context — data is abstract statistical (AR(2) process) without
+    any label indicating what the time series represents
+  - 'DE-03: No annotation pointing to the key insight that the PACF cutoff at lag
+    2 identifies this as an AR(2) process; a small annotation at lag 2 would elevate
+    storytelling'
+  image_description: |-
+    Light render (plot-light.png):
+      Background: Warm off-white (#FAF8F1) — correct, not pure white.
+      Chrome: Title "acf-pacf · javascript · chartjs · anyplot.ai" in bold 22px dark text, clearly readable. Y-axis labels "ACF" and "PACF" in 14px/600 weight, readable. X-axis "Lag" label on bottom chart only, 14px/600 weight. Tick labels 14px, clearly readable. 95% CI legend between panels at 13px, readable. All text dark on light background.
+      Data: ACF bars in brand green (#009E73) showing exponential decay from lag 0 (=1.0) through lag 30. PACF bars in green for positive lags 1-2 (significant), red (#AE3030, Imprint palette position 5, semantic negative anchor) for small negative values. Horizontal dashed CI lines at ±0.127. ACF x-axis shows even lags (0, 2, 4…30); PACF shows all lags (1–30).
+      Legibility verdict: PASS — all text clearly readable; no element unreadable.
+
+    Dark render (plot-dark.png):
+      Background: Warm near-black (#1A1A17) — correct, not pure black.
+      Chrome: Title light-colored on dark background, clearly readable. Y-axis labels, tick labels, and x-axis label all correctly light-colored. 95% CI legend text light-colored. No dark-on-dark failures observed. Brand green #009E73 clearly visible on dark surface.
+      Data: Colors identical to light render — green bars and red bars are the same hex values. CI dashed lines remain visible. Data presentation unchanged from light to dark (only chrome flips).
+      Legibility verdict: PASS — all text clearly readable against dark background; no dark-on-dark failures; correct theme-adaptive chrome throughout.
+  criteria_checklist:
+    visual_quality:
+      score: 27
+      max: 30
+      items:
+      - id: VQ-01
+        name: Text Legibility
+        score: 7
+        max: 8
+        passed: true
+        comment: 'All fonts explicitly set (title 22px DOM, axis labels 14px/600,
+          ticks 14px, legend 13px). Minor: ACF x-axis sparse ticks (maxTicksLimit:16)
+          vs PACF all-30-lags creates slight inconsistency.'
+      - id: VQ-02
+        name: No Overlap
+        score: 6
+        max: 6
+        passed: true
+        comment: No text or element overlaps in either render.
+      - id: VQ-03
+        name: Element Visibility
+        score: 5
+        max: 6
+        passed: true
+        comment: ACF and significant PACF bars well-sized (barThickness:7). Very small
+          high-lag PACF bars statistically correct but barely visible — not a code
+          defect.
+      - id: VQ-04
+        name: Color Accessibility
+        score: 2
+        max: 2
+        passed: true
+        comment: 'Semantic green/red CVD-safe: bar position (above/below zero) provides
+          redundant encoding.'
+      - id: VQ-05
+        name: Layout & Canvas
+        score: 3
+        max: 4
+        passed: true
+        comment: 'Good flex two-panel layout with generous padding. Minor: y-axis
+          renders to ±1.5 (Chart.js padding beyond suggestedMin/Max), creating unused
+          vertical space for mostly-positive ACF and near-zero PACF data.'
+      - id: VQ-06
+        name: Axis Labels & Title
+        score: 2
+        max: 2
+        passed: true
+        comment: '"ACF", "PACF", "Lag" are descriptive and correctly placed.'
+      - id: VQ-07
+        name: Palette Compliance
+        score: 2
+        max: 2
+        passed: true
+        comment: 'First series #009E73 ✓; red #AE3030 for negative is semantic exception
+          ✓; backgrounds #FAF8F1/#1A1A17 ✓; theme-adaptive chrome both renders ✓.'
+    design_excellence:
+      score: 12
+      max: 20
+      items:
+      - id: DE-01
+        name: Aesthetic Sophistication
+        score: 5
+        max: 8
+        passed: true
+        comment: Thoughtful semantic coloring, custom DOM title for layout control,
+          clean axis styling. Above well-configured default but not publication-ready.
+      - id: DE-02
+        name: Visual Refinement
+        score: 4
+        max: 6
+        passed: true
+        comment: X-axis grid removed, borders hidden, generous padding, custom zero-line
+          gridline highlight via scriptable callback. Solid refinements above defaults.
+      - id: DE-03
+        name: Data Storytelling
+        score: 3
+        max: 6
+        passed: true
+        comment: AR(2) data choice perfectly demonstrates diagnostic insight; green/red
+          adds emphasis. No annotation pointing to the key PACF cutoff at lag 2.
+    spec_compliance:
+      score: 15
+      max: 15
+      items:
+      - id: SC-01
+        name: Plot Type
+        score: 5
+        max: 5
+        passed: true
+        comment: Correct bar-based stem plot in two vertically stacked panels.
+      - id: SC-02
+        name: Required Features
+        score: 4
+        max: 4
+        passed: true
+        comment: ACF top/PACF bottom, 95% CI dashed lines, lag 0 in ACF, PACF starts
+          at lag 1, 30 lags, axes labeled.
+      - id: SC-03
+        name: Data Mapping
+        score: 3
+        max: 3
+        passed: true
+        comment: X = lag number, Y = correlation value, correctly mapped.
+      - id: SC-04
+        name: Title & Legend
+        score: 3
+        max: 3
+        passed: true
+        comment: Title "acf-pacf · javascript · chartjs · anyplot.ai" exact format;
+          95% CI legend correct.
+    data_quality:
+      score: 14
+      max: 15
+      items:
+      - id: DQ-01
+        name: Feature Coverage
+        score: 6
+        max: 6
+        passed: true
+        comment: AR(2) demonstrates exponential ACF decay, PACF cutoff at model order,
+          lag-0=1.0, positive and negative correlations, significance bands.
+      - id: DQ-02
+        name: Realistic Context
+        score: 4
+        max: 5
+        passed: true
+        comment: Plausible neutral statistical time series; slightly abstract without
+          explicit real-world domain label.
+      - id: DQ-03
+        name: Appropriate Scale
+        score: 4
+        max: 4
+        passed: true
+        comment: AR(2) with phi1=0.7, phi2=0.2; N=240; all values within [-1, 1] —
+          statistically correct.
+    code_quality:
+      score: 9
+      max: 10
+      items:
+      - id: CQ-01
+        name: KISS Structure
+        score: 2
+        max: 3
+        passed: true
+        comment: Helper functions (lcgRand, stdNormal, computeACF, computePACF, makePane,
+          ciLine, yAxis) justified by browser LCG requirement and math complexity,
+          but deviate from flat-script KISS ideal.
+      - id: CQ-02
+        name: Reproducibility
+        score: 2
+        max: 2
+        passed: true
+        comment: Fixed LCG seed (_seed=42) ensures deterministic output.
+      - id: CQ-03
+        name: Clean Imports
+        score: 2
+        max: 2
+        passed: true
+        comment: No imports; all globals (Chart, ANYPLOT_TOKENS) used correctly.
+      - id: CQ-04
+        name: Code Elegance
+        score: 2
+        max: 2
+        passed: true
+        comment: Clean, well-commented; no fake UI elements; appropriate complexity.
+      - id: CQ-05
+        name: Output & API
+        score: 1
+        max: 1
+        passed: true
+        comment: Correct orientation directive; current Chart.js 4.4.7 API.
+    library_mastery:
+      score: 7
+      max: 10
+      items:
+      - id: LM-01
+        name: Idiomatic Usage
+        score: 4
+        max: 5
+        passed: true
+        comment: Good use of mixed dataset types (bar+line), scriptable options API,
+          token-based color mapping, responsive/animation:false pattern.
+      - id: LM-02
+        name: Distinctive Features
+        score: 3
+        max: 5
+        passed: true
+        comment: Uses Chart.js-specific scriptable options (grid color callback),
+          legend filter callback, and mixed chart type datasets. Could be replicated
+          with some effort in other libraries.
+  verdict: APPROVED
+impl_tags:
+  dependencies: []
+  techniques:
+  - subplots
+  - custom-legend
+  patterns:
+  - data-generation
+  dataprep:
+  - time-series
+  styling:
+  - grid-styling