Update

app.js

@@ -25,6 +25,7 @@ import {
 import { drawChart, CHART_PALETTE, pushRing } from './ui/charts.js'
 import { defaultModeFromMeta } from './shared/chart-types.js'
 import { createMetricsDashboard } from './ui/dashboard.js'
+import { getChartFocus } from './ui/chart-focus.js'
 import {
   buildFleetRoster,
   summarizeFleet,
@@ -354,6 +355,172 @@ function paint(canvasId, lines, opts = {}) {
   drawChart($(canvasId), lines, { ...opts, maxPoints: seriesMax() })
 }
 
+const overviewFocus = getChartFocus()
+
+/** @type {Array<{ id: string, title: string, subtitle: string, canvasId: string, lines: () => any[], opts: () => object }>} */
+const OVERVIEW_FOCUS = [
+  {
+    id: 'system.cpu',
+    title: 'CPU',
+    subtitle: 'system.cpu',
+    canvasId: 'chart-cpu',
+    lines: () => overviewCpuLines().lines,
+    opts: () => ({ ...anomalyOptsFor('system.cpu'), ...overviewCpuLines().opts }),
+  },
+  {
+    id: 'system.ram',
+    title: 'Memory',
+    subtitle: 'system.ram',
+    canvasId: 'chart-ram',
+    lines: () => [{ values: series.ram, color: CHART_PALETTE.ram }],
+    opts: () => ({
+      ...anomalyOptsFor(anomalyByChart.has('mem.available') ? 'mem.available' : 'system.ram'),
+      mode: 'area',
+    }),
+  },
+  {
+    id: 'system.net',
+    title: 'Network',
+    subtitle: 'system.net',
+    canvasId: 'chart-net',
+    lines: () =>
+      series.netTx.length >= 2
+        ? [
+            { values: series.net, color: CHART_PALETTE.net, label: 'rx' },
+            { values: series.netTx, color: CHART_PALETTE.disk, label: 'tx' },
+          ]
+        : [{ values: series.net, color: CHART_PALETTE.net, label: 'rx' }],
+    opts: () => ({ ...anomalyOptsFor('system.net'), mode: 'area' }),
+  },
+  {
+    id: 'system.io',
+    title: 'Disk I/O',
+    subtitle: 'system.io',
+    canvasId: 'chart-io',
+    lines: () =>
+      series.ioWrite.length >= 2
+        ? [
+            { values: series.io, color: CHART_PALETTE.disk, label: 'read' },
+            { values: series.ioWrite, color: CHART_PALETTE.cpuIowait, label: 'write' },
+          ]
+        : [{ values: series.io, color: CHART_PALETTE.disk, label: 'io' }],
+    opts: () => ({ ...anomalyOptsFor('system.io'), mode: 'area' }),
+  },
+  {
+    id: 'system.load',
+    title: 'Load',
+    subtitle: 'system.load',
+    canvasId: 'chart-load',
+    lines: () => [{ values: series.load, color: CHART_PALETTE.load }],
+    opts: () => ({ ...anomalyOptsFor('system.load'), mode: 'line' }),
+  },
+  {
+    id: 'explore',
+    title: 'Spotlight',
+    subtitle: () => exploreChartId,
+    canvasId: 'chart-explore',
+    lines: () => [{ values: series.explore, color: CHART_PALETTE.explore }],
+    opts: () => ({
+      ...anomalyOptsFor(exploreChartId),
+      mode: defaultModeFromMeta(chartCatalog[exploreChartId] || { chartType: 'line' }),
+    }),
+  },
+]
+
+function overviewCpuLines() {
+  if (els.compareToggle?.checked && peerCpu.size > 0) {
+    const lines = [...peerCpu.entries()].slice(0, 5).map(([id, values], i) => ({
+      values,
+      color: CHART_PALETTE.compare[i % CHART_PALETTE.compare.length],
+      label: id.slice(0, 8),
+      fill: false,
+    }))
+    return { lines, opts: { mode: 'line' } }
+  }
+  const lines = [
+    { values: series.cpuUser.length ? series.cpuUser : series.cpu, color: CHART_PALETTE.cpuUser, label: 'user', fill: false },
+    { values: series.cpuSystem, color: CHART_PALETTE.cpuSystem, label: 'system', fill: false },
+    { values: series.cpuIowait, color: CHART_PALETTE.cpuIowait, label: 'iowait', fill: false },
+  ].filter((l) => l.values.length >= 2)
+  if (!lines.length) {
+    return {
+      lines: [{ values: series.cpu, color: CHART_PALETTE.cpuUser, label: 'used' }],
+      opts: { mode: 'area' },
+    }
+  }
+  return { lines, opts: { mode: 'stacked' } }
+}
+
+function openOverviewFocus(focusId) {
+  const idx = OVERVIEW_FOCUS.findIndex((p) => p.id === focusId)
+  if (idx < 0) return
+  const openAt = (i) => {
+    const panel = OVERVIEW_FOCUS[(i + OVERVIEW_FOCUS.length) % OVERVIEW_FOCUS.length]
+    const sub =
+      typeof panel.subtitle === 'function' ? panel.subtitle() : panel.subtitle
+    overviewFocus.open({
+      id: panel.id,
+      title: panel.title,
+      subtitle: sub,
+      paint: (canvas) => {
+        drawChart(canvas, panel.lines(), { ...panel.opts(), maxPoints: seriesMax() })
+      },
+      onPrev: () => openAt(i - 1),
+      onNext: () => openAt(i + 1),
+      actions: [
+        {
+          id: 'charts',
+          label: 'Open in Charts',
+          title: 'Jump to Charts wall',
+          onClick: () => {
+            overviewFocus.close()
+            const chartId = panel.id === 'explore' ? exploreChartId : panel.id
+            showView('charts')
+            metricsDashboard.scrollToChart?.(chartId)
+            metricsDashboard.openFocus?.(chartId)
+          },
+        },
+      ],
+    })
+    overviewFocus.refresh()
+  }
+  openAt(idx)
+}
+
+function bindOverviewFocus() {
+  const panels = [
+    [els.panelCpu, 'system.cpu'],
+    [els.panelRam, 'system.ram'],
+    [els.panelNet, 'system.net'],
+    [els.panelIo, 'system.io'],
+    [els.panelLoad, 'system.load'],
+    [els.panelExplore, 'explore'],
+  ]
+  for (const [panel, id] of panels) {
+    if (!panel || panel.dataset.focusBound) continue
+    panel.dataset.focusBound = '1'
+    panel.classList.add('chart-panel--focusable')
+    if (!panel.querySelector('.chart-focus-btn')) {
+      const btn = document.createElement('button')
+      btn.type = 'button'
+      btn.className = 'btn btn-ghost chart-focus-btn'
+      btn.title = 'Fullscreen'
+      btn.setAttribute('aria-label', 'Fullscreen')
+      btn.textContent = '⛶'
+      const header = panel.querySelector('header')
+      header?.appendChild(btn)
+      btn.addEventListener('click', (ev) => {
+        ev.stopPropagation()
+        openOverviewFocus(id)
+      })
+    }
+    panel.addEventListener('dblclick', (ev) => {
+      if (ev.target instanceof HTMLElement && ev.target.closest('select,button,a,label')) return
+      openOverviewFocus(id)
+    })
+  }
+}
+
 let overviewPaintRaf = 0
 /** Coalesce Overview redraws into one frame to avoid spark blink. */
 function scheduleRedrawAll() {
@@ -458,45 +625,21 @@ function anomalyOptsFor(chart) {
 }
 
 function redrawCpu() {
-  const opts = anomalyOptsFor('system.cpu')
+  const { lines, opts } = overviewCpuLines()
+  paint('chart-cpu', lines, { ...anomalyOptsFor('system.cpu'), ...opts })
   if (els.compareToggle?.checked && peerCpu.size > 0) {
-    const lines = [...peerCpu.entries()].slice(0, 5).map(([id, values], i) => ({
-      values,
-      color: CHART_PALETTE.compare[i % CHART_PALETTE.compare.length],
-      label: id.slice(0, 8),
-      fill: false,
-    }))
-    paint('chart-cpu', lines, opts)
     if (els.chartCpuLabel) els.chartCpuLabel.textContent = `compare · ${lines.length} peers`
+  } else if (els.chartCpuLabel) {
+    els.chartCpuLabel.textContent = 'system.cpu'
+  }
   if (els.legendCpu) {
-      els.legendCpu.innerHTML = lines
+    els.legendCpu.innerHTML = (lines.length ? lines : [{ color: CHART_PALETTE.cpuUser, label: 'used' }])
       .map(
         (l) =>
           `<span style="--swatch:${l.color}">${escapeHtml(l.label || '')}</span>`
       )
       .join('')
   }
-  } else {
-    const lines = [
-      { values: series.cpuUser.length ? series.cpuUser : series.cpu, color: CHART_PALETTE.cpuUser, label: 'user', fill: false },
-      { values: series.cpuSystem, color: CHART_PALETTE.cpuSystem, label: 'system', fill: false },
-      { values: series.cpuIowait, color: CHART_PALETTE.cpuIowait, label: 'iowait', fill: false },
-    ].filter((l) => l.values.length >= 2)
-    if (!lines.length) {
-      paint('chart-cpu', [{ values: series.cpu, color: CHART_PALETTE.cpuUser }], {
-        ...opts,
-        mode: 'area',
-      })
-    } else {
-      paint('chart-cpu', lines, { ...opts, mode: 'stacked' })
-    }
-    if (els.chartCpuLabel) els.chartCpuLabel.textContent = 'system.cpu'
-    if (els.legendCpu) {
-      els.legendCpu.innerHTML = (lines.length ? lines : [{ color: CHART_PALETTE.cpuUser, label: 'used' }])
-        .map((l) => `<span style="--swatch:${l.color}">${l.label}</span>`)
-        .join('')
-    }
-  }
 }
 
 function redrawAll() {
@@ -511,10 +654,7 @@ function redrawAll() {
   )
   paint(
     'chart-net',
-    [
-      { values: series.net, color: CHART_PALETTE.net, label: 'rx' },
-      { values: series.netTx, color: CHART_PALETTE.disk, label: 'tx' },
-    ].filter((l) => l.values.length >= 2).length
+    series.netTx.length >= 2
       ? [
           { values: series.net, color: CHART_PALETTE.net },
           { values: series.netTx, color: CHART_PALETTE.disk },
@@ -524,10 +664,7 @@ function redrawAll() {
   )
   paint(
     'chart-io',
-    [
-      { values: series.io, color: CHART_PALETTE.disk },
-      { values: series.ioWrite, color: CHART_PALETTE.cpuIowait },
-    ].filter((l) => l.values.length >= 2).length
+    series.ioWrite.length >= 2
       ? [
           { values: series.io, color: CHART_PALETTE.disk },
           { values: series.ioWrite, color: CHART_PALETTE.cpuIowait },
@@ -548,6 +685,11 @@ function redrawAll() {
       mode: defaultModeFromMeta(chartCatalog[exploreChartId] || { chartType: 'line' }),
     }
   )
+  // Live-update Overview focus only (Charts wall owns its own paint callback)
+  if (overviewFocus.isOpen()) {
+    const id = overviewFocus.currentId()
+    if (OVERVIEW_FOCUS.some((p) => p.id === id)) overviewFocus.refresh()
+  }
 }
 
 function updateActivePeerChip() {
@@ -1470,6 +1612,7 @@ async function restorePeersOnBoot() {
 
 setOnline(false)
 syncSettingsUi()
+bindOverviewFocus()
 showView(loadBookmarks().length ? 'fleet' : 'connect')
 renderBookmarks()
 renderPeers()

docs/DASHBOARD.md

@@ -98,6 +98,7 @@ Do not name third-party products in code, commits, or user-facing copy.
 - [x] Related ranking boosted by alert weights when no MC window
 - [x] Drag-reorder pinned charts
 - [x] Keyboard shortcuts on Charts (`Space` play, `1–5` presets, `/` search, `f` force, `b` board, `c` correlate, `r` reset, `Esc` clear)
+- [x] Fullscreen chart focus (Charts wall + Overview) — double-click / ⛶, `Esc` / `←` `→`
 
 ---
 
@@ -125,6 +126,7 @@ Do not name third-party products in code, commits, or user-facing copy.
 | `shared/related-metrics.js` | Related-chart ranking (taxonomy + Pearson) |
 | `server/services/weights.js` | Metric Correlations scoring (ks2 / volume / AR / value) |
 | `ui/dashboard.js` | Metrics wall controller + Correlate mode |
+| `ui/chart-focus.js` | Fullscreen chart overlay (shared) |
 | `ui/charts.js` | Canvas paint + hover helpers |
 | `ui/data-manager.js` | Settings → Data (retention / prune / usage) |
 | `ui/logs.js` | System Log tab (journal default) |

index.html

@@ -182,7 +182,7 @@
           <div>
             <p class="dash-kicker">Metrics</p>
             <h1 class="dash-title">Charts</h1>
-            <p class="page-subtitle">Scroll freely · <kbd>⌃</kbd>/<kbd>⇧</kbd>+scroll zooms · <kbd>Space</kbd> · <kbd>/</kbd> · <kbd>1–5</kbd></p>
+            <p class="page-subtitle">Double-click or <span class="page-hint-ico">⛶</span> for fullscreen · <kbd>Space</kbd> · <kbd>/</kbd> · <kbd>1–5</kbd> · <kbd>Esc</kbd></p>
           </div>
         </header>
         <div class="metrics-toolbar" id="metrics-timebar">

ui/chart-focus.js

@@ -0,0 +1,271 @@
+/**
+ * Fullscreen chart focus overlay — shared by Charts wall + Overview sparks.
+ */
+
+/**
+ * @typedef {{
+ *   id?: string,
+ *   title?: string,
+ *   subtitle?: string,
+ *   units?: string,
+ *   status?: string,
+ *   paint: (canvas: HTMLCanvasElement) => void,
+ *   onClose?: () => void,
+ *   onPrev?: (() => void)|null,
+ *   onNext?: (() => void)|null,
+ *   actions?: Array<{ id: string, label: string, title?: string, active?: boolean, onClick: () => void }>,
+ * }} FocusOpts
+ */
+
+/**
+ * @returns {{
+ *   open: (opts: FocusOpts) => void,
+ *   close: () => void,
+ *   isOpen: () => boolean,
+ *   currentId: () => string,
+ *   refresh: () => void,
+ *   updateChrome: (patch: Partial<FocusOpts>) => void,
+ *   setLegend: (html: string) => void,
+ *   el: HTMLElement,
+ * }}
+ */
+export function createChartFocus() {
+  const root = document.createElement('div')
+  root.id = 'chart-focus'
+  root.className = 'chart-focus hidden'
+  root.tabIndex = -1
+  root.setAttribute('role', 'dialog')
+  root.setAttribute('aria-modal', 'true')
+  root.setAttribute('aria-labelledby', 'chart-focus-title')
+  root.innerHTML = `
+    <div class="chart-focus-backdrop" data-focus-close="1"></div>
+    <div class="chart-focus-stage">
+      <header class="chart-focus-head">
+        <div class="chart-focus-titles">
+          <p class="chart-focus-kicker muted" id="chart-focus-sub"></p>
+          <h2 id="chart-focus-title">Chart</h2>
+          <p class="chart-focus-meta muted">
+            <span id="chart-focus-units"></span>
+            <span id="chart-focus-status"></span>
+          </p>
+        </div>
+        <div class="chart-focus-actions" id="chart-focus-actions"></div>
+        <button type="button" class="btn btn-ghost chart-focus-close" data-focus-close="1" title="Close (Esc)" aria-label="Close fullscreen">✕</button>
+      </header>
+      <div class="chart-focus-body">
+        <button type="button" class="chart-focus-nav chart-focus-prev" id="chart-focus-prev" title="Previous chart (←)" aria-label="Previous chart">‹</button>
+        <div class="chart-focus-canvas-wrap">
+          <canvas id="chart-focus-canvas"></canvas>
+        </div>
+        <button type="button" class="chart-focus-nav chart-focus-next" id="chart-focus-next" title="Next chart (→)" aria-label="Next chart">›</button>
+      </div>
+      <footer class="chart-focus-foot">
+        <div id="chart-focus-legend" class="chart-focus-legend"></div>
+        <p class="chart-focus-hint muted"><kbd>Esc</kbd> close · <kbd>←</kbd><kbd>→</kbd> navigate · <kbd>Space</kbd> pause · <kbd>1</kbd>–<kbd>5</kbd> window</p>
+      </footer>
+    </div>
+  `
+  document.body.appendChild(root)
+
+  const titleEl = /** @type {HTMLElement} */ (root.querySelector('#chart-focus-title'))
+  const subEl = /** @type {HTMLElement} */ (root.querySelector('#chart-focus-sub'))
+  const unitsEl = /** @type {HTMLElement} */ (root.querySelector('#chart-focus-units'))
+  const statusEl = /** @type {HTMLElement} */ (root.querySelector('#chart-focus-status'))
+  const actionsEl = /** @type {HTMLElement} */ (root.querySelector('#chart-focus-actions'))
+  const legendEl = /** @type {HTMLElement} */ (root.querySelector('#chart-focus-legend'))
+  const canvas = /** @type {HTMLCanvasElement} */ (root.querySelector('#chart-focus-canvas'))
+  const prevBtn = /** @type {HTMLButtonElement} */ (root.querySelector('#chart-focus-prev'))
+  const nextBtn = /** @type {HTMLButtonElement} */ (root.querySelector('#chart-focus-next'))
+
+  /** @type {FocusOpts|null} */
+  let current = null
+  let resizeObs = /** @type {ResizeObserver|null} */ (null)
+  let openRaf = 0
+
+  function paintNow() {
+    if (!current?.paint || !canvas) return
+    try {
+      current.paint(canvas)
+    } catch {
+      // ignore paint errors in focus
+    }
+  }
+
+  function schedulePaint() {
+    if (openRaf) return
+    openRaf = requestAnimationFrame(() => {
+      openRaf = 0
+      paintNow()
+    })
+  }
+
+  function syncNav() {
+    const hasPrev = Boolean(current?.onPrev)
+    const hasNext = Boolean(current?.onNext)
+    prevBtn.classList.toggle('hidden', !hasPrev)
+    nextBtn.classList.toggle('hidden', !hasNext)
+    prevBtn.disabled = !hasPrev
+    nextBtn.disabled = !hasNext
+  }
+
+  function syncActions() {
+    const actions = current?.actions || []
+    actionsEl.innerHTML = ''
+    for (const a of actions) {
+      const btn = document.createElement('button')
+      btn.type = 'button'
+      btn.className = 'btn btn-ghost' + (a.active ? ' is-active' : '')
+      btn.dataset.focusAction = a.id
+      btn.textContent = a.label
+      if (a.title) btn.title = a.title
+      btn.addEventListener('click', (ev) => {
+        ev.stopPropagation()
+        a.onClick()
+      })
+      actionsEl.appendChild(btn)
+    }
+  }
+
+  /**
+   * @param {Partial<FocusOpts>} patch
+   */
+  function updateChrome(patch = {}) {
+    if (!current) return
+    current = { ...current, ...patch }
+    titleEl.textContent = current.title || current.id || 'Chart'
+    subEl.textContent = current.subtitle || current.id || ''
+    unitsEl.textContent = current.units ? String(current.units) : ''
+    statusEl.textContent = current.status ? String(current.status) : ''
+    syncNav()
+    if (patch.actions) syncActions()
+  }
+
+  /**
+   * Optional legend HTML from the host (dimension chips).
+   * @param {string} html
+   */
+  function setLegend(html) {
+    legendEl.innerHTML = html || ''
+  }
+
+  /**
+   * @param {FocusOpts} opts
+   */
+  function open(opts) {
+    current = { ...opts }
+    updateChrome(opts)
+    syncActions()
+    root.classList.remove('hidden')
+    requestAnimationFrame(() => root.classList.add('is-open'))
+    document.body.classList.add('chart-focus-open')
+    schedulePaint()
+    if (!resizeObs && typeof ResizeObserver !== 'undefined') {
+      resizeObs = new ResizeObserver(() => schedulePaint())
+      const wrap = root.querySelector('.chart-focus-canvas-wrap')
+      if (wrap) resizeObs.observe(wrap)
+    }
+    try {
+      root.focus({ preventScroll: true })
+    } catch {
+      // ignore
+    }
+  }
+
+  function close() {
+    if (!current) return
+    const onClose = current.onClose
+    current = null
+    root.classList.remove('is-open')
+    const hide = () => {
+      root.classList.add('hidden')
+      legendEl.innerHTML = ''
+      document.body.classList.remove('chart-focus-open')
+    }
+    // Allow exit animation; fall back if reduced motion
+    let done = false
+    const finish = () => {
+      if (done) return
+      done = true
+      hide()
+    }
+    root.addEventListener('transitionend', finish, { once: true })
+    setTimeout(finish, 220)
+    onClose?.()
+  }
+
+  function isOpen() {
+    return Boolean(current) && !root.classList.contains('hidden')
+  }
+
+  function currentId() {
+    return current?.id || ''
+  }
+
+  function refresh() {
+    if (!isOpen()) return
+    schedulePaint()
+  }
+
+  root.addEventListener('click', (ev) => {
+    const t = /** @type {HTMLElement} */ (ev.target)
+    if (t?.closest?.('[data-focus-close]')) {
+      ev.preventDefault()
+      close()
+    }
+  })
+
+  prevBtn.addEventListener('click', (ev) => {
+    ev.stopPropagation()
+    current?.onPrev?.()
+  })
+  nextBtn.addEventListener('click', (ev) => {
+    ev.stopPropagation()
+    current?.onNext?.()
+  })
+
+  window.addEventListener('keydown', (ev) => {
+    if (!isOpen()) return
+    const tag = (ev.target && /** @type {HTMLElement} */ (ev.target).tagName) || ''
+    if (tag === 'INPUT' || tag === 'TEXTAREA' || tag === 'SELECT') return
+    if (ev.key === 'Escape') {
+      ev.preventDefault()
+      ev.stopPropagation()
+      close()
+    } else if (ev.key === 'ArrowLeft') {
+      if (current?.onPrev) {
+        ev.preventDefault()
+        current.onPrev()
+      }
+    } else if (ev.key === 'ArrowRight') {
+      if (current?.onNext) {
+        ev.preventDefault()
+        current.onNext()
+      }
+    }
+  })
+
+  // Keep canvas sharp on DPR / window resize
+  window.addEventListener('resize', () => {
+    if (isOpen()) schedulePaint()
+  })
+
+  return {
+    open,
+    close,
+    isOpen,
+    currentId,
+    refresh,
+    updateChrome,
+    setLegend,
+    el: root,
+  }
+}
+
+/** @type {ReturnType<typeof createChartFocus>|null} */
+let sharedFocus = null
+
+/** App-wide singleton so Overview + Charts share one overlay. */
+export function getChartFocus() {
+  if (!sharedFocus) sharedFocus = createChartFocus()
+  return sharedFocus
+}

ui/dashboard.js

@@ -12,6 +12,7 @@ import {
 } from '../shared/chart-types.js'
 import { drawChart, hoverIndexFromEvent, padLeftFor, pushDim, seriesColor } from './charts.js'
 import { chartOptionLabel, metricCardSubtitle } from '../shared/container-names.js'
+import { getChartFocus } from './chart-focus.js'
 
 const GROUPS = ['average', 'min', 'max', 'sum']
 
@@ -90,6 +91,7 @@ function smoothScrollIntoView(el, block = 'start') {
  */
 export function createMetricsDashboard(opts) {
   const prefs = () => opts.getPrefs?.() || {}
+  const focus = getChartFocus()
 
   const state = {
     filter: '',
@@ -532,6 +534,208 @@ export function createMetricsDashboard(opts) {
     return { dims, hidden }
   }
 
+  /**
+   * Build drawable series + draw opts for a chart card.
+   * @param {string} id
+   */
+  function buildPaintModel(id) {
+    const card = state.cards.get(id)
+    if (!card) return null
+    const { dims, hidden } = sortedDims(card, id)
+    const mode = normalizeChartMode(card.mode || defaultModeFromMeta(card.meta))
+    card.mode = mode
+    /** @type {Array<{ values: number[], color: string, label: string, hidden: boolean, fill?: boolean }>} */
+    const lines = []
+    let i = 0
+    for (const dim of dims) {
+      const values = card.dims.get(dim) || []
+      lines.push({
+        values,
+        color: seriesColor(i),
+        label: dim,
+        hidden: hidden.has(dim),
+        fill: mode === 'area' ? true : mode === 'line' ? false : undefined,
+      })
+      i++
+    }
+    const anomaly = opts.getAnomaly?.(id) || null
+    const emptyMsg =
+      card.status === 'loading'
+        ? card.emptyReason || 'Loading…'
+        : card.status === 'error'
+          ? card.emptyReason || 'Error'
+          : card.status === 'empty'
+            ? card.emptyReason || 'No data'
+            : 'No data'
+    const units = card.meta?.units || ''
+    const showY = mode !== 'pie'
+    return {
+      card,
+      dims,
+      hidden,
+      mode,
+      lines,
+      anomaly,
+      units,
+      emptyMsg,
+      drawOpts: {
+        mode,
+        maxPoints: maxPoints(),
+        showYAxis: showY,
+        padLeft: padLeftFor(units, showY),
+        hoverIndex: mode === 'pie' ? null : state.hoverIndex,
+        threshold: mode === 'pie' ? null : anomaly?.threshold ?? null,
+        severity: anomaly?.severity || null,
+        emptyMessage: emptyMsg,
+        dimmed: false,
+        units,
+        windowSeconds: mode === 'pie' ? null : state.afterSeconds,
+        endOffset: state.endOffset,
+      },
+    }
+  }
+
+  /** Ordered chart ids currently on the wall (for focus prev/next). */
+  function wallChartIds() {
+    const ids = []
+    for (const el of opts.els.wall?.querySelectorAll('[data-chart-id]') || []) {
+      const id = el.getAttribute('data-chart-id')
+      if (id) ids.push(id)
+    }
+    return ids.length ? ids : [...state.cardEls.keys()]
+  }
+
+  /**
+   * @param {string} id
+   * @param {HTMLCanvasElement} canvas
+   * @param {ReturnType<typeof buildPaintModel>} model
+   */
+  function paintCanvas(id, canvas, model) {
+    if (!model || !canvas) return
+    drawChart(canvas, model.lines, model.drawOpts)
+  }
+
+  function focusLegendHtml(model) {
+    if (!model) return ''
+    const show = model.lines.slice(0, LEGEND_CHIP_CAP)
+    const extra = Math.max(0, model.lines.length - LEGEND_CHIP_CAP)
+    const unitSuffix = model.units ? ` ${model.units}` : ''
+    return (
+      show
+        .map((line) => {
+          const last = line.values[line.values.length - 1]
+          const text = `${line.label}${last != null ? ` ${formatVal(last)}${unitSuffix}` : ''}`
+          return `<span class="dim-chip${line.hidden ? ' off' : ''}" style="--dim-color:${line.color}">${escapeHtml(text)}</span>`
+        })
+        .join('') +
+      (extra ? `<span class="dim-chip-more muted">+${extra}</span>` : '')
+    )
+  }
+
+  function syncFocusChrome(id) {
+    if (!focus.isOpen() || focus.currentId() !== id) return
+    const model = buildPaintModel(id)
+    const catalog = opts.getCatalog() || {}
+    const meta = catalog[id] || state.cards.get(id)?.meta || {}
+    const status =
+      model?.card?.status === 'ok' && model.card.source && model.card.source !== 'memory'
+        ? model.card.source
+        : model?.card?.status === 'ok'
+          ? ''
+          : model?.card?.status || ''
+    focus.updateChrome({
+      id,
+      title: meta.title || id,
+      subtitle: metricCardSubtitle(id, meta),
+      units: meta.units || model?.units || '',
+      status,
+      actions: focusActionsFor(id),
+      onPrev: () => focusStep(-1),
+      onNext: () => focusStep(1),
+    })
+    focus.setLegend(focusLegendHtml(model))
+  }
+
+  function focusActionsFor(id) {
+    const card = state.cards.get(id)
+    const mode = card?.mode || 'line'
+    return [
+      {
+        id: 'pin',
+        label: state.pinned.has(id) ? '★ Pin' : '☆ Pin',
+        title: 'Pin to board',
+        active: state.pinned.has(id),
+        onClick: () => {
+          togglePin(id)
+          syncFocusChrome(id)
+        },
+      },
+      {
+        id: 'type',
+        label: CHART_MODE_LABEL[mode] || mode,
+        title: chartModeHint(mode),
+        onClick: () => {
+          cycleChartType(id)
+          syncFocusChrome(id)
+          focus.refresh()
+        },
+      },
+      {
+        id: 'related',
+        label: 'Related',
+        title: 'Find related charts',
+        onClick: () => {
+          focus.close()
+          showRelated(id)
+        },
+      },
+    ]
+  }
+
+  function openFocus(id) {
+    if (!id) return
+    ensureCard(id, (opts.getCatalog() || {})[id] || {})
+    if (!state.cards.get(id)?.dims?.size) {
+      fetchChart(id).catch(() => {})
+    }
+    const catalog = opts.getCatalog() || {}
+    const meta = catalog[id] || {}
+    focus.open({
+      id,
+      title: meta.title || id,
+      subtitle: metricCardSubtitle(id, meta),
+      units: meta.units || '',
+      paint: (canvas) => {
+        const model = buildPaintModel(id)
+        paintCanvas(id, canvas, model)
+      },
+      onPrev: () => focusStep(-1),
+      onNext: () => focusStep(1),
+      actions: focusActionsFor(id),
+      onClose: () => {
+        const el = state.cardEls.get(id)
+        el?.classList.remove('is-focused')
+      },
+    })
+    for (const el of state.cardEls.values()) el.classList.remove('is-focused')
+    state.cardEls.get(id)?.classList.add('is-focused')
+    syncFocusChrome(id)
+    focus.refresh()
+  }
+
+  /** @param {number} delta */
+  function focusStep(delta) {
+    const ids = wallChartIds()
+    if (!ids.length) return
+    const cur = focus.currentId()
+    let idx = ids.indexOf(cur)
+    if (idx < 0) idx = 0
+    const next = ids[(idx + delta + ids.length) % ids.length]
+    openFocus(next)
+    const el = state.cardEls.get(next)
+    if (el && !state.visible.has(next)) smoothScrollIntoView(el, 'center')
+  }
+
   function paintCard(id) {
     const article = state.cardEls.get(id)
     if (!article) return
@@ -541,8 +745,14 @@ export function createMetricsDashboard(opts) {
     const legend = article.querySelector('.metric-card-legend')
     article.classList.toggle('pinned', state.pinned.has(id))
     article.classList.toggle('related', state.relatedIds.has(id))
+    article.classList.toggle('is-focused', focus.isOpen() && focus.currentId() === id)
     const pinBtn = article.querySelector('.metric-pin-btn')
     if (pinBtn) pinBtn.textContent = state.pinned.has(id) ? '★' : '☆'
+    const typeBtn = article.querySelector('.metric-type-btn')
+    if (typeBtn && card) {
+      typeBtn.textContent = CHART_MODE_LABEL[card.mode] || card.mode
+      typeBtn.title = chartModeHint(card.mode)
+    }
     // Never dim the card during SWR — opacity/filter changes look like a blink
     article.classList.remove('updating')
     if (statusEl) {
@@ -564,64 +774,25 @@ export function createMetricsDashboard(opts) {
         weightChip.classList.add('hidden')
       }
     }
-    if (!card || !canvas) return
+    const model = buildPaintModel(id)
+    if (!card || !canvas || !model) return
     const height = cardHeightFor(id, card)
     const heightPx = `${height}px`
     if (canvas.style.height !== heightPx) canvas.style.height = heightPx
     updateHighlightBand(id)
-    const { dims, hidden } = sortedDims(card, id)
-    const mode = normalizeChartMode(card.mode || defaultModeFromMeta(card.meta))
-    card.mode = mode
-    const lines = []
-    let i = 0
-    for (const dim of dims) {
-      const values = card.dims.get(dim) || []
-      lines.push({
-        values,
-        color: seriesColor(i),
-        label: dim,
-        hidden: hidden.has(dim),
-        fill: mode === 'area' ? true : mode === 'line' ? false : undefined,
-      })
-      i++
-    }
-    const anomaly = opts.getAnomaly?.(id) || null
-    if (anomaly?.severity) article.dataset.severity = anomaly.severity
+    if (model.anomaly?.severity) article.dataset.severity = model.anomaly.severity
     else delete article.dataset.severity
-    article.dataset.chartMode = mode
-    const emptyMsg =
-      card.status === 'loading'
-        ? card.emptyReason || 'Loading…'
-        : card.status === 'error'
-          ? card.emptyReason || 'Error'
-          : card.status === 'empty'
-            ? card.emptyReason || 'No data'
-            : 'No data'
-    const units = card.meta?.units || ''
-    const showY = mode !== 'pie'
-    drawChart(canvas, lines, {
-      mode,
-      maxPoints: maxPoints(),
-      showYAxis: showY,
-      padLeft: padLeftFor(units, showY),
-      hoverIndex: mode === 'pie' ? null : state.hoverIndex,
-      threshold: mode === 'pie' ? null : anomaly?.threshold ?? null,
-      severity: anomaly?.severity || null,
-      emptyMessage: emptyMsg,
-      dimmed: false,
-      units,
-      windowSeconds: mode === 'pie' ? null : state.afterSeconds,
-      endOffset: state.endOffset,
-    })
-    updateCardTooltip(article, id, card, lines, units)
+    article.dataset.chartMode = model.mode
+    paintCanvas(id, canvas, model)
+    updateCardTooltip(article, id, card, model.lines, model.units)
     const statsEl = article.querySelector('.metric-card-stats')
     if (statsEl && article.classList.contains('expanded')) {
-      statsEl.innerHTML = renderStatsHtml(card, dims, hidden, units)
+      statsEl.innerHTML = renderStatsHtml(card, model.dims, model.hidden, model.units)
     }
     if (legend && !card.updating) {
-      const show = lines.slice(0, LEGEND_CHIP_CAP)
-      const extra = Math.max(0, lines.length - LEGEND_CHIP_CAP)
-      const unitSuffix = units ? ` ${units}` : ''
+      const show = model.lines.slice(0, LEGEND_CHIP_CAP)
+      const extra = Math.max(0, model.lines.length - LEGEND_CHIP_CAP)
+      const unitSuffix = model.units ? ` ${model.units}` : ''
       const nextHtml =
         show
           .map((line) => {
@@ -644,6 +815,10 @@ export function createMetricsDashboard(opts) {
         })
       }
     }
+    if (focus.isOpen() && focus.currentId() === id) {
+      syncFocusChrome(id)
+      focus.refresh()
+    }
   }
 
   /**
@@ -1384,6 +1559,7 @@ export function createMetricsDashboard(opts) {
           <button type="button" class="btn btn-ghost metric-pin-btn" title="Pin">${state.pinned.has(id) ? '★' : '☆'}</button>
           <button type="button" class="btn btn-ghost metric-related-btn" title="Find related">⇢</button>
           <button type="button" class="btn btn-ghost metric-type-btn" title="${escapeAttr(chartModeHint(card.mode))}">${escapeHtml(CHART_MODE_LABEL[card.mode] || card.mode)}</button>
+          <button type="button" class="btn btn-ghost metric-focus-btn" title="Fullscreen (double-click)" aria-label="Fullscreen">⛶</button>
           <span class="metric-card-status muted"></span>
         </div>
       </header>
@@ -1391,6 +1567,7 @@ export function createMetricsDashboard(opts) {
         <canvas height="${height}"></canvas>
         <div class="metric-highlight-band hidden" aria-hidden="true"></div>
         <span class="metric-weight-chip hidden"></span>
+        <button type="button" class="metric-focus-fab" title="Fullscreen" aria-label="Open fullscreen">⛶</button>
       </div>
       <div class="metric-card-legend"></div>
       <div class="metric-card-stats hidden"></div>
@@ -1421,6 +1598,12 @@ export function createMetricsDashboard(opts) {
       ev.stopPropagation()
       cycleChartType(id)
     })
+    const openFocusHandler = (ev) => {
+      ev.stopPropagation()
+      openFocus(id)
+    }
+    article.querySelector('.metric-focus-btn')?.addEventListener('click', openFocusHandler)
+    article.querySelector('.metric-focus-fab')?.addEventListener('click', openFocusHandler)
     bindResizeHandle(article)
     article.querySelector('.metric-card-title')?.addEventListener('click', (ev) => {
       ev.stopPropagation()
@@ -1437,14 +1620,9 @@ export function createMetricsDashboard(opts) {
     })
     article.addEventListener('dblclick', (ev) => {
       if (ev.target instanceof HTMLElement && ev.target.closest('.metric-card-actions')) return
-      article.classList.add('expanded')
-      const statsEl = article.querySelector('.metric-card-stats')
-      if (statsEl) {
-        statsEl.classList.remove('hidden')
-        const { dims, hidden } = sortedDims(card, id)
-        statsEl.innerHTML = renderStatsHtml(card, dims, hidden, card.meta?.units || '')
-      }
-      showRelated(id)
+      if (ev.target instanceof HTMLElement && ev.target.closest('.metric-resize')) return
+      ev.preventDefault()
+      openFocus(id)
     })
     state.cardEls.set(id, article)
     state.observer?.observe(article)
@@ -1822,6 +2000,17 @@ export function createMetricsDashboard(opts) {
         }
         return
       }
+      if (focus.isOpen()) {
+        if (ev.key === ' ' || ev.code === 'Space') {
+          ev.preventDefault()
+          setPlaying(!state.playing)
+        } else if (ev.key >= '1' && ev.key <= '5') {
+          const presets = ['1m', '5m', '15m', '1h', '6h']
+          setPreset(presets[Number(ev.key) - 1])
+        }
+        // Esc / arrows handled by chart-focus
+        return
+      }
       if (ev.key === ' ' || ev.code === 'Space') {
         ev.preventDefault()
         setPlaying(!state.playing)
@@ -1930,6 +2119,8 @@ export function createMetricsDashboard(opts) {
     redrawVisible,
     scrollToChart,
     focusChartAt,
+    openFocus,
+    closeFocus: () => focus.close(),
     showRelated,
     clearRelated,
     setBoardOnly,

ui/styles.css

@@ -772,13 +772,42 @@ body.is-offline .offline-banner:not(.hidden) {
 
 .chart-panel header {
   display: flex;
-  align-items: baseline;
+  align-items: center;
   justify-content: space-between;
   gap: 10px;
   margin-bottom: 4px;
   flex-shrink: 0;
 }
 
+.chart-panel--focusable {
+  position: relative;
+  cursor: pointer;
+  transition:
+    border-color 0.18s ease,
+    box-shadow 0.18s ease,
+    transform 0.18s ease;
+}
+
+.chart-panel--focusable:hover {
+  border-color: color-mix(in srgb, var(--accent-primary) 32%, var(--border-color));
+  box-shadow: 0 6px 22px rgba(0, 0, 0, 0.2);
+}
+
+.chart-panel .chart-focus-btn {
+  opacity: 0;
+  min-width: 1.8rem !important;
+  padding: 2px 6px !important;
+  font-size: 12px !important;
+  margin-left: auto;
+  flex-shrink: 0;
+  transition: opacity 0.15s ease, background 0.15s ease;
+}
+
+.chart-panel--focusable:hover .chart-focus-btn,
+.chart-panel--focusable:focus-within .chart-focus-btn {
+  opacity: 1;
+}
+
 .chart-panel h3 {
   margin: 0;
   font-size: 12px;
@@ -1536,7 +1565,7 @@ button.metrics-tf.thin-history:not(.active) {
   padding: 12px 14px 8px;
   border-radius: 14px;
   background:
-    linear-gradient(180deg, rgba(255, 255, 255, 0.03), transparent 48%),
+    linear-gradient(180deg, rgba(255, 255, 255, 0.035), transparent 42%),
     var(--bg-secondary);
   border: 1px solid var(--border-color);
   min-height: 0;
@@ -1557,6 +1586,59 @@ button.metrics-tf.thin-history:not(.active) {
   border-color: color-mix(in srgb, var(--accent-primary) 42%, var(--border-color));
 }
 
+.metric-card.is-focused {
+  border-color: color-mix(in srgb, var(--accent-primary) 55%, var(--border-color));
+  box-shadow: var(--shadow-glow);
+}
+
+.metric-focus-fab {
+  position: absolute;
+  top: 8px;
+  left: 8px;
+  z-index: 4;
+  width: 30px;
+  height: 30px;
+  border: 1px solid var(--border-strong);
+  border-radius: 9px;
+  background: color-mix(in srgb, var(--bg-elevated) 88%, transparent);
+  color: var(--text-secondary);
+  font-size: 13px;
+  line-height: 1;
+  cursor: pointer;
+  opacity: 0;
+  transform: translateY(2px);
+  backdrop-filter: blur(8px);
+  -webkit-backdrop-filter: blur(8px);
+  transition:
+    opacity 0.16s ease,
+    transform 0.16s ease,
+    color 0.16s ease,
+    border-color 0.16s ease;
+}
+
+.metric-card:hover .metric-focus-fab,
+.metric-card:focus-within .metric-focus-fab {
+  opacity: 1;
+  transform: translateY(0);
+}
+
+.metric-focus-fab:hover {
+  color: var(--accent-primary);
+  border-color: color-mix(in srgb, var(--accent-primary) 45%, var(--border-color));
+}
+
+.metric-focus-btn {
+  min-width: 1.8rem !important;
+  padding: 2px 6px !important;
+  font-size: 12px !important;
+  opacity: 0.55;
+}
+
+.metric-card:hover .metric-focus-btn,
+.metric-card:focus-within .metric-focus-btn {
+  opacity: 1;
+}
+
 .metric-card[data-chart-mode='pie'] canvas {
   cursor: default;
 }
@@ -1780,7 +1862,14 @@ html[data-theme='light'] .metric-card canvas {
 .metric-card-actions {
   display: flex;
   align-items: center;
-  gap: 6px;
+  gap: 4px;
+  flex-shrink: 0;
+}
+
+.metric-card-actions .btn {
+  min-height: 26px;
+  padding: 2px 7px !important;
+  font-size: 11px !important;
 }
 
 .metric-card canvas.panning {
@@ -2827,3 +2916,249 @@ code {
     opacity: 1;
   }
 }
+
+/* ─── Fullscreen chart focus ─── */
+body.chart-focus-open {
+  overflow: hidden;
+}
+
+.chart-focus {
+  position: fixed;
+  inset: 0;
+  z-index: 1200;
+  display: flex;
+  align-items: stretch;
+  justify-content: center;
+  padding: max(12px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right))
+    max(12px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity 0.18s ease;
+}
+
+.chart-focus.hidden {
+  display: none;
+}
+
+.chart-focus.is-open {
+  opacity: 1;
+  pointer-events: auto;
+}
+
+.chart-focus-backdrop {
+  position: absolute;
+  inset: 0;
+  background:
+    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(52, 211, 153, 0.08), transparent 55%),
+    rgba(4, 6, 10, 0.72);
+  backdrop-filter: blur(14px);
+  -webkit-backdrop-filter: blur(14px);
+}
+
+html[data-theme='light'] .chart-focus-backdrop {
+  background:
+    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(52, 211, 153, 0.1), transparent 55%),
+    rgba(243, 245, 248, 0.78);
+}
+
+.chart-focus-stage {
+  position: relative;
+  z-index: 1;
+  display: flex;
+  flex-direction: column;
+  width: min(1280px, 100%);
+  max-height: 100%;
+  margin: auto;
+  padding: 16px 18px 12px;
+  border-radius: 18px;
+  border: 1px solid var(--border-strong);
+  background:
+    linear-gradient(180deg, rgba(255, 255, 255, 0.04), transparent 36%),
+    var(--bg-secondary);
+  box-shadow: var(--shadow-md), 0 0 0 1px rgba(52, 211, 153, 0.08);
+  transform: translateY(10px) scale(0.985);
+  transition: transform 0.2s ease;
+}
+
+.chart-focus.is-open .chart-focus-stage {
+  transform: translateY(0) scale(1);
+}
+
+.chart-focus-head {
+  display: flex;
+  align-items: flex-start;
+  gap: 12px;
+  margin-bottom: 10px;
+  flex-shrink: 0;
+}
+
+.chart-focus-titles {
+  min-width: 0;
+  flex: 1;
+}
+
+.chart-focus-kicker {
+  margin: 0 0 2px;
+  font-size: 11px;
+  font-family: var(--font-mono);
+  letter-spacing: 0.02em;
+}
+
+.chart-focus-head h2 {
+  margin: 0;
+  font-size: clamp(18px, 2.4vw, 26px);
+  font-weight: 650;
+  letter-spacing: -0.02em;
+  color: var(--text-primary);
+}
+
+.chart-focus-meta {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px 14px;
+  margin: 4px 0 0;
+  font-size: 11px;
+  font-family: var(--font-mono);
+}
+
+.chart-focus-actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+  align-items: center;
+  justify-content: flex-end;
+}
+
+.chart-focus-actions .btn.is-active {
+  color: var(--accent-primary);
+  border-color: color-mix(in srgb, var(--accent-primary) 40%, var(--border-color));
+}
+
+.chart-focus-close {
+  min-width: 2.2rem !important;
+  font-size: 14px !important;
+  flex-shrink: 0;
+}
+
+.chart-focus-body {
+  position: relative;
+  flex: 1 1 auto;
+  min-height: 0;
+  display: grid;
+  grid-template-columns: 40px 1fr 40px;
+  gap: 4px;
+  align-items: stretch;
+}
+
+.chart-focus-canvas-wrap {
+  min-height: clamp(280px, 58vh, 720px);
+  border-radius: 12px;
+  overflow: hidden;
+  background: rgba(0, 0, 0, 0.22);
+  border: 1px solid var(--border-color);
+}
+
+html[data-theme='light'] .chart-focus-canvas-wrap {
+  background: rgba(15, 23, 42, 0.03);
+}
+
+.chart-focus-canvas-wrap canvas {
+  width: 100%;
+  height: 100%;
+  display: block;
+}
+
+.chart-focus-nav {
+  align-self: center;
+  width: 36px;
+  height: 64px;
+  border: 1px solid var(--border-color);
+  border-radius: 12px;
+  background: color-mix(in srgb, var(--bg-elevated) 80%, transparent);
+  color: var(--text-secondary);
+  font-size: 28px;
+  line-height: 1;
+  cursor: pointer;
+  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
+}
+
+.chart-focus-nav:hover:not(:disabled) {
+  color: var(--accent-primary);
+  border-color: color-mix(in srgb, var(--accent-primary) 40%, var(--border-color));
+  background: var(--bg-hover);
+}
+
+.chart-focus-nav:disabled,
+.chart-focus-nav.hidden {
+  opacity: 0;
+  pointer-events: none;
+}
+
+.chart-focus-foot {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  justify-content: space-between;
+  gap: 10px;
+  margin-top: 10px;
+  flex-shrink: 0;
+}
+
+.chart-focus-legend {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+  min-height: 22px;
+  flex: 1;
+}
+
+.chart-focus-hint {
+  margin: 0;
+  font-size: 11px;
+  white-space: nowrap;
+}
+
+.chart-focus-hint kbd {
+  display: inline-block;
+  padding: 1px 5px;
+  border-radius: 5px;
+  border: 1px solid var(--border-color);
+  background: var(--bg-tertiary);
+  font-family: var(--font-mono);
+  font-size: 10px;
+}
+
+.page-hint-ico {
+  opacity: 0.85;
+}
+
+@media (max-width: 720px) {
+  .chart-focus-body {
+    grid-template-columns: 1fr;
+  }
+  .chart-focus-nav {
+    display: none;
+  }
+  .chart-focus-stage {
+    padding: 12px;
+    border-radius: 14px;
+  }
+  .chart-focus-hint {
+    white-space: normal;
+  }
+  .chart-panel .chart-focus-btn,
+  .metric-focus-fab,
+  .metric-focus-btn {
+    opacity: 1;
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .chart-focus,
+  .chart-focus-stage,
+  .metric-focus-fab,
+  .metric-card,
+  .chart-panel--focusable {
+    transition: none !important;
+  }
+}