Fix health trends range selector; add day navigation and chart click

- Fix keepPreviousData v4→v5: import keepPreviousData from @tanstack/react-query
  and use as placeholderData so charts don't blank out when switching ranges
- Normalise all metric dates to YYYY-MM-DD in queryFn so XAxis values and
  ReferenceLine x values always match
- Add allDays query (last 365 days) for snapshot navigation, keyed under
  ['health-metrics', 'all'] so UploadPage invalidation covers it
- Arrow nav (← →) in snapshot header steps through available days
- Clicking any trend chart data point loads that day in the snapshot
- Blue dashed ReferenceLine marks the selected day in every chart

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/HealthPage.jsx

@@ -1,12 +1,12 @@
 import { useState, useMemo } from 'react'
-import { useQuery } from '@tanstack/react-query'
+import { useQuery, keepPreviousData } from '@tanstack/react-query'
 import {
-  AreaChart, Area, BarChart, Bar,
+  AreaChart, Area, BarChart, Bar, ReferenceLine,
   XAxis, YAxis, CartesianGrid, Tooltip, ResponsiveContainer,
 } from 'recharts'
 import { format, subDays } from 'date-fns'
 import api from '../utils/api'
-import { formatSleep, formatWeight, formatHeartRate } from '../utils/format'
+import { formatSleep } from '../utils/format'
 
 const RANGES = [
   { label: '1W', days: 7 },
@@ -17,9 +17,14 @@ const RANGES = [
   { label: '1Y', days: 365 },
 ]
 
-const tooltipStyle = { background: '#111827', border: '1px solid #374151', borderRadius: 8, fontSize: 12 }
+const tooltipStyle = {
+  background: '#111827', border: '1px solid #374151', borderRadius: 8, fontSize: 12,
+}
 
-// ── Daily Snapshot helpers ──────────────────────────────────────────────────
+// Normalise any date string to YYYY-MM-DD so XAxis values and ReferenceLine x match.
+const d10 = (s) => (s || '').slice(0, 10)
+
+// ── Daily Snapshot ──────────────────────────────────────────────────────────
 
 function fmtTime(ts) {
   if (!ts) return '--'
@@ -52,22 +57,22 @@ function HrvBadge({ status }) {
   return <span className={`text-xs px-2 py-0.5 rounded-full border ${cls}`}>{status}</span>
 }
 
-function Stat({ label, value, unit, sub, accent }) {
+function NavArrow({ onClick, disabled, children }) {
-  const accentCls = accent === 'red' ? 'text-rose-400' : accent === 'blue' ? 'text-blue-400' : accent === 'green' ? 'text-green-400' : 'text-white'
   return (
-    <div>
+    <button
-      <p className="text-xs text-gray-500 mb-0.5">{label}</p>
+      onClick={onClick}
-      <div className="flex items-baseline gap-1">
+      disabled={disabled}
-        <span className={`text-2xl font-bold ${accentCls}`}>{value}</span>
+      className="w-7 h-7 flex items-center justify-center rounded-lg text-gray-400
-        {unit && <span className="text-xs text-gray-500">{unit}</span>}
+                 hover:text-white hover:bg-gray-800 disabled:opacity-20 disabled:cursor-default
-      </div>
+                 transition-colors text-base font-medium"
-      {sub && <p className="text-xs text-gray-500 mt-0.5">{sub}</p>}
+    >
-    </div>
+      {children}
+    </button>
   )
 }
 
-function DailySnapshot({ latest, avg30 }) {
+function DailySnapshot({ day, avg30, onOlder, onNewer, hasOlder, hasNewer }) {
-  if (!latest) return (
+  if (!day) return (
     <div className="text-center py-10 text-gray-600">
       <p className="text-3xl mb-2">📊</p>
       <p>No health data yet</p>
@@ -75,71 +80,67 @@ function DailySnapshot({ latest, avg30 }) {
     </div>
   )
 
-  const dateLabel = latest.date
+  const dateLabel = day.date ? format(new Date(day.date), 'EEEE, d MMMM yyyy') : 'Latest'
-    ? format(new Date(latest.date), 'EEEE, d MMMM yyyy')
+  const hasSleepStages = day.sleep_deep_s || day.sleep_light_s || day.sleep_rem_s
-    : 'Latest'
-
-  const hasSleepStages = latest.sleep_deep_s || latest.sleep_light_s || latest.sleep_rem_s
   const stepsGoal = 10000
-  const stepsPct = latest.steps ? Math.min(100, (latest.steps / stepsGoal * 100).toFixed(0)) : 0
+  const stepsPct = day.steps ? Math.min(100, Math.round(day.steps / stepsGoal * 100)) : 0
 
-  const stressLabel = !latest.avg_stress ? null :
+  const stressLabel = !day.avg_stress ? null
-    latest.avg_stress < 25 ? 'Restful' :
+    : day.avg_stress < 25 ? 'Restful'
-    latest.avg_stress < 50 ? 'Low' :
+    : day.avg_stress < 50 ? 'Low'
-    latest.avg_stress < 75 ? 'Medium' : 'High'
+    : day.avg_stress < 75 ? 'Medium' : 'High'
-  const stressColor = !latest.avg_stress ? 'text-white' :
+  const stressColor = !day.avg_stress ? 'text-white'
-    latest.avg_stress < 25 ? 'text-green-400' :
+    : day.avg_stress < 25 ? 'text-green-400'
-    latest.avg_stress < 50 ? 'text-yellow-400' :
+    : day.avg_stress < 50 ? 'text-yellow-400'
-    latest.avg_stress < 75 ? 'text-orange-400' : 'text-red-400'
+    : day.avg_stress < 75 ? 'text-orange-400' : 'text-red-400'
 
   return (
     <div className="space-y-4">
-      <div>
+
+      {/* Header + arrows */}
+      <div className="flex items-center gap-3">
+        <NavArrow onClick={onOlder} disabled={!hasOlder}>←</NavArrow>
+        <div className="min-w-0">
           <p className="text-xs text-gray-500 uppercase tracking-wide">Daily snapshot</p>
-        <h2 className="text-xl font-semibold text-white mt-0.5">{dateLabel}</h2>
+          <h2 className="text-xl font-semibold text-white leading-tight">{dateLabel}</h2>
+        </div>
+        <NavArrow onClick={onNewer} disabled={!hasNewer}>→</NavArrow>
       </div>
 
-      {/* Top row: Sleep (wide) + Heart/HRV */}
+      {/* Sleep (wide) + Heart / HRV */}
       <div className="grid grid-cols-1 lg:grid-cols-3 gap-4">
 
-        {/* Sleep card — 2/3 width on desktop */}
         <div className="lg:col-span-2 bg-gray-900 rounded-xl border border-gray-800 p-5 space-y-3">
           <div className="flex items-center justify-between">
             <h3 className="text-sm font-medium text-gray-300">Sleep</h3>
-            <div className="flex items-center gap-2">
+            {day.sleep_score != null && (
-              {latest.sleep_score != null && (
               <span className="text-xs px-2 py-0.5 rounded-full border border-indigo-400/30 bg-indigo-400/10 text-indigo-300">
-                  Score {Math.round(latest.sleep_score)}
+                Score {Math.round(day.sleep_score)}
               </span>
             )}
           </div>
-          </div>
-
           <div className="flex items-end gap-3">
             <span className="text-4xl font-bold text-white tracking-tight">
-              {formatSleep(latest.sleep_duration_s)}
+              {formatSleep(day.sleep_duration_s)}
             </span>
-            {latest.sleep_start && latest.sleep_end && (
+            {day.sleep_start && day.sleep_end && (
               <span className="text-sm text-gray-500 pb-1">
-                {fmtTime(latest.sleep_start)} → {fmtTime(latest.sleep_end)}
+                {fmtTime(day.sleep_start)} → {fmtTime(day.sleep_end)}
               </span>
             )}
           </div>
-
           {hasSleepStages ? (
             <>
               <SleepStagesBar
-                deep={latest.sleep_deep_s}
+                deep={day.sleep_deep_s} light={day.sleep_light_s}
-                light={latest.sleep_light_s}
+                rem={day.sleep_rem_s} awake={day.sleep_awake_s}
-                rem={latest.sleep_rem_s}
-                awake={latest.sleep_awake_s}
               />
               <div className="flex flex-wrap gap-x-5 gap-y-1.5">
                 {[
-                  ['Deep', latest.sleep_deep_s, '#6366f1'],
+                  ['Deep',  day.sleep_deep_s,  '#6366f1'],
-                  ['REM', latest.sleep_rem_s, '#8b5cf6'],
+                  ['REM',   day.sleep_rem_s,   '#8b5cf6'],
-                  ['Light', latest.sleep_light_s, '#a78bfa'],
+                  ['Light', day.sleep_light_s, '#a78bfa'],
-                  ['Awake', latest.sleep_awake_s, '#4b5563'],
+                  ['Awake', day.sleep_awake_s, '#4b5563'],
                 ].map(([label, secs, color]) => secs ? (
                   <div key={label} className="flex items-center gap-1.5">
                     <div className="w-2.5 h-2.5 rounded-sm" style={{ backgroundColor: color }} />
@@ -150,53 +151,47 @@ function DailySnapshot({ latest, avg30 }) {
                 ) : null)}
               </div>
             </>
-          ) : !latest.sleep_duration_s ? (
+          ) : !day.sleep_duration_s ? (
             <p className="text-sm text-gray-600">No sleep data</p>
           ) : null}
         </div>
 
-        {/* Heart & HRV card — 1/3 width */}
         <div className="bg-gray-900 rounded-xl border border-gray-800 p-5 space-y-4">
           <h3 className="text-sm font-medium text-gray-300">Heart & HRV</h3>
-
           <div>
             <p className="text-xs text-gray-500 mb-0.5">Resting HR</p>
             <div className="flex items-baseline gap-1.5">
               <span className="text-3xl font-bold text-rose-400">
-                {latest.resting_hr ? Math.round(latest.resting_hr) : '--'}
+                {day.resting_hr ? Math.round(day.resting_hr) : '--'}
               </span>
               <span className="text-sm text-gray-500">bpm</span>
             </div>
-            {avg30?.resting_hr && latest.resting_hr && (
+            {avg30?.resting_hr && day.resting_hr && (
               <p className="text-xs text-gray-500 mt-0.5">
                 30d avg {Math.round(avg30.resting_hr)} bpm
-                {latest.resting_hr < avg30.resting_hr
+                {day.resting_hr < avg30.resting_hr
                   ? <span className="text-green-400 ml-1">↓</span>
-                  : latest.resting_hr > avg30.resting_hr
+                  : day.resting_hr > avg30.resting_hr
                   ? <span className="text-red-400 ml-1">↑</span>
                   : null}
               </p>
             )}
           </div>
-
           <div>
             <p className="text-xs text-gray-500 mb-0.5">HRV</p>
             <div className="flex items-baseline gap-1.5 flex-wrap">
               <span className="text-3xl font-bold text-violet-400">
-                {latest.hrv_nightly_avg ? Math.round(latest.hrv_nightly_avg) : '--'}
+                {day.hrv_nightly_avg ? Math.round(day.hrv_nightly_avg) : '--'}
               </span>
               <span className="text-sm text-gray-500">ms</span>
-              <HrvBadge status={latest.hrv_status} />
+              <HrvBadge status={day.hrv_status} />
             </div>
           </div>
-
+          {day.avg_hr_day && (
-          {latest.avg_hr_day && (
             <div>
               <p className="text-xs text-gray-500 mb-0.5">Avg HR (day)</p>
               <div className="flex items-baseline gap-1.5">
-                <span className="text-xl font-semibold text-orange-400">
+                <span className="text-xl font-semibold text-orange-400">{Math.round(day.avg_hr_day)}</span>
-                  {Math.round(latest.avg_hr_day)}
-                </span>
                 <span className="text-xs text-gray-500">bpm</span>
               </div>
             </div>
@@ -207,78 +202,69 @@ function DailySnapshot({ latest, avg30 }) {
       {/* Activity strip */}
       <div className="grid grid-cols-2 sm:grid-cols-4 gap-3">
 
-        {/* Steps */}
         <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
           <p className="text-xs text-gray-500 mb-1">Steps</p>
           <div className="flex items-baseline gap-1 mb-2">
             <span className="text-2xl font-bold text-yellow-400">
-              {latest.steps ? latest.steps.toLocaleString() : '--'}
+              {day.steps ? day.steps.toLocaleString() : '--'}
             </span>
           </div>
-          {latest.steps ? (
+          {day.steps ? (
             <>
               <div className="h-1.5 bg-gray-800 rounded-full overflow-hidden">
-                <div className="h-full bg-yellow-400 rounded-full transition-all" style={{ width: `${stepsPct}%` }} />
+                <div className="h-full bg-yellow-400 rounded-full transition-all"
+                  style={{ width: `${stepsPct}%` }} />
               </div>
               <p className="text-xs text-gray-600 mt-1">{stepsPct}% of {stepsGoal.toLocaleString()}</p>
             </>
           ) : null}
-          {latest.floors_climbed ? (
+          {day.floors_climbed
-            <p className="text-xs text-gray-500 mt-1">{latest.floors_climbed} floors</p>
+            ? <p className="text-xs text-gray-500 mt-1">{day.floors_climbed} floors</p>
-          ) : null}
+            : null}
         </div>
 
-        {/* Calories */}
         <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
           <p className="text-xs text-gray-500 mb-1">Calories</p>
           <div className="flex items-baseline gap-1">
             <span className="text-2xl font-bold text-white">
-              {latest.total_calories
+              {day.total_calories
-                ? Math.round(latest.total_calories)
+                ? Math.round(day.total_calories)
-                : latest.active_calories
+                : day.active_calories ? Math.round(day.active_calories) : '--'}
-                ? Math.round(latest.active_calories)
-                : '--'}
             </span>
             <span className="text-xs text-gray-500">kcal</span>
           </div>
-          {latest.active_calories && latest.total_calories && (
+          {day.active_calories && day.total_calories && (
-            <p className="text-xs text-gray-500 mt-1">
+            <p className="text-xs text-gray-500 mt-1">Active {Math.round(day.active_calories)} kcal</p>
-              Active {Math.round(latest.active_calories)} kcal
-            </p>
           )}
         </div>
 
-        {/* Stress */}
         <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
           <p className="text-xs text-gray-500 mb-1">Stress</p>
           <div className="flex items-baseline gap-1">
             <span className={`text-2xl font-bold ${stressColor}`}>
-              {latest.avg_stress ? Math.round(latest.avg_stress) : '--'}
+              {day.avg_stress ? Math.round(day.avg_stress) : '--'}
             </span>
-            {latest.avg_stress && <span className="text-xs text-gray-500">/100</span>}
+            {day.avg_stress && <span className="text-xs text-gray-500">/100</span>}
           </div>
           {stressLabel && <p className="text-xs text-gray-500 mt-1">{stressLabel}</p>}
         </div>
 
-        {/* SpO2 or VO2 Max */}
         <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
-          {latest.spo2_avg ? (
+          {day.spo2_avg ? (
             <>
               <p className="text-xs text-gray-500 mb-1">SpO2</p>
               <div className="flex items-baseline gap-1">
-                <span className="text-2xl font-bold text-sky-400">{latest.spo2_avg.toFixed(1)}</span>
+                <span className="text-2xl font-bold text-sky-400">{day.spo2_avg.toFixed(1)}</span>
                 <span className="text-xs text-gray-500">%</span>
               </div>
             </>
-          ) : latest.vo2max ? (
+          ) : day.vo2max ? (
             <>
               <p className="text-xs text-gray-500 mb-1">VO2 Max</p>
               <div className="flex items-baseline gap-1">
-                <span className="text-2xl font-bold text-blue-400">{latest.vo2max.toFixed(1)}</span>
+                <span className="text-2xl font-bold text-blue-400">{day.vo2max.toFixed(1)}</span>
               </div>
-              {latest.fitness_age && (
+              {day.fitness_age && <p className="text-xs text-gray-500 mt-1">Fitness age {day.fitness_age}</p>}
-                <p className="text-xs text-gray-500 mt-1">Fitness age {latest.fitness_age}</p>
-              )}
             </>
           ) : (
             <>
@@ -294,14 +280,22 @@ function DailySnapshot({ latest, avg30 }) {
 
 // ── Trend Charts ────────────────────────────────────────────────────────────
 
-function MetricChart({ data, dataKey, color, formatter, height = 140 }) {
+function MetricChart({ data, dataKey, color, formatter, height = 140, selectedDate, onDayClick }) {
   const vals = data.filter(d => d[dataKey] != null)
   if (!vals.length) return (
     <div className="flex items-center justify-center text-gray-600 text-xs" style={{ height }}>No data</div>
   )
   return (
     <ResponsiveContainer width="100%" height={height}>
-      <AreaChart data={data} margin={{ top: 4, right: 4, bottom: 4, left: 0 }}>
+      <AreaChart
+        data={data}
+        margin={{ top: 4, right: 4, bottom: 4, left: 0 }}
+        style={{ cursor: onDayClick ? 'pointer' : 'default' }}
+        onClick={evt => {
+          const p = evt?.activePayload?.[0]?.payload
+          if (p?.date && onDayClick) onDayClick(p.date)
+        }}
+      >
         <defs>
           <linearGradient id={`grad-${dataKey}`} x1="0" y1="0" x2="0" y2="1">
             <stop offset="5%" stopColor={color} stopOpacity={0.3} />
@@ -315,6 +309,9 @@ function MetricChart({ data, dataKey, color, formatter, height = 140 }) {
           tickFormatter={formatter} />
         <Tooltip contentStyle={tooltipStyle} labelFormatter={d => format(new Date(d), 'MMM d, yyyy')}
           formatter={v => [formatter ? formatter(v) : v?.toFixed(1)]} />
+        {selectedDate && (
+          <ReferenceLine x={selectedDate} stroke="#60a5fa" strokeWidth={1.5} strokeDasharray="4 2" />
+        )}
         <Area type="monotone" dataKey={dataKey} stroke={color} strokeWidth={2}
           fill={`url(#grad-${dataKey})`} dot={false} connectNulls={false} isAnimationActive={false} />
       </AreaChart>
@@ -322,25 +319,39 @@ function MetricChart({ data, dataKey, color, formatter, height = 140 }) {
   )
 }
 
-function SleepChart({ data }) {
+function SleepChart({ data, selectedDate, onDayClick }) {
   const chartData = data.map(d => ({
-    date: d.date,
+    date: d.date,   // already normalised to YYYY-MM-DD
     deep:  d.sleep_deep_s  ? +(d.sleep_deep_s  / 3600).toFixed(2) : null,
     rem:   d.sleep_rem_s   ? +(d.sleep_rem_s   / 3600).toFixed(2) : null,
     light: d.sleep_light_s ? +(d.sleep_light_s / 3600).toFixed(2) : null,
     awake: d.sleep_awake_s ? +(d.sleep_awake_s / 3600).toFixed(2) : null,
   }))
   const hasData = chartData.some(d => d.deep || d.rem || d.light)
-  if (!hasData) return <div className="flex items-center justify-center h-36 text-gray-600 text-xs">No sleep data</div>
+  if (!hasData) return (
+    <div className="flex items-center justify-center h-36 text-gray-600 text-xs">No sleep data</div>
+  )
   return (
     <ResponsiveContainer width="100%" height={140}>
-      <BarChart data={chartData} margin={{ top: 4, right: 4, bottom: 4, left: 0 }} barSize={6}>
+      <BarChart
+        data={chartData}
+        margin={{ top: 4, right: 4, bottom: 4, left: 0 }}
+        barSize={6}
+        style={{ cursor: onDayClick ? 'pointer' : 'default' }}
+        onClick={evt => {
+          const p = evt?.activePayload?.[0]?.payload
+          if (p?.date && onDayClick) onDayClick(p.date)
+        }}
+      >
         <CartesianGrid strokeDasharray="3 3" stroke="#1f2937" vertical={false} />
         <XAxis dataKey="date" tick={{ fontSize: 10, fill: '#6b7280' }} axisLine={false} tickLine={false}
           tickFormatter={d => format(new Date(d), 'MMM d')} interval="preserveStartEnd" />
         <YAxis tick={{ fontSize: 10, fill: '#6b7280' }} axisLine={false} tickLine={false} width={24}
           tickFormatter={v => `${v}h`} />
         <Tooltip contentStyle={tooltipStyle} labelFormatter={d => format(new Date(d), 'MMM d, yyyy')} />
+        {selectedDate && (
+          <ReferenceLine x={selectedDate} stroke="#60a5fa" strokeWidth={1.5} strokeDasharray="4 2" />
+        )}
         <Bar dataKey="deep"  name="Deep"  stackId="a" fill="#6366f1" />
         <Bar dataKey="rem"   name="REM"   stackId="a" fill="#8b5cf6" />
         <Bar dataKey="light" name="Light" stackId="a" fill="#a78bfa" />
@@ -350,44 +361,92 @@ function SleepChart({ data }) {
   )
 }
 
-// ── Page ────────────────────────────────────────────────────────────────────
+// ── Page ─────────────────────────────────────────────────────────────────────
 
 export default function HealthPage() {
   const [rangeDays, setRangeDays] = useState(7)
+  const [selectedDateStr, setSelectedDateStr] = useState(null)   // YYYY-MM-DD or null = latest
 
-  const fromDate = useMemo(() => format(subDays(new Date(), rangeDays), 'yyyy-MM-dd'), [rangeDays])
+  const fromDate = useMemo(
+    () => format(subDays(new Date(), rangeDays), 'yyyy-MM-dd'),
+    [rangeDays],
+  )
 
   const { data: summary } = useQuery({
     queryKey: ['health-summary'],
     queryFn: () => api.get('/health-metrics/summary').then(r => r.data),
   })
 
-  const { data: metrics, isLoading } = useQuery({
+  // Full history for snapshot navigation.
-    queryKey: ['health-metrics', rangeDays],
+  // Key starts with ['health-metrics'] so UploadPage invalidation hits it automatically.
+  const { data: allDays } = useQuery({
+    queryKey: ['health-metrics', 'all'],
     queryFn: () =>
-      api.get('/health-metrics/', {
+      api.get('/health-metrics/', { params: { limit: 365 } })
-        params: { from_date: fromDate, limit: rangeDays + 1 },
+        .then(r => r.data.map(d => ({ ...d, date: d10(d.date) }))),
-      }).then(r => r.data.slice().reverse()),
-    keepPreviousData: true,
   })
 
-  const latest = summary?.latest
+  // Trend window (changes with range selector).
-  const avg30 = summary?.avg_30d
+  // Dates normalised to YYYY-MM-DD so XAxis values match ReferenceLine x.
+  const { data: rawMetrics, isLoading } = useQuery({
+    queryKey: ['health-metrics', rangeDays],
+    queryFn: () =>
+      api.get('/health-metrics/', { params: { from_date: fromDate, limit: rangeDays + 1 } })
+        .then(r => r.data.slice().reverse().map(d => ({ ...d, date: d10(d.date) }))),
+    placeholderData: keepPreviousData,
+  })
+  const metrics = rawMetrics || []
+
+  // Snapshot navigation: newest-first sorted list of all available days
+  const allDaysSorted = useMemo(
+    () => (allDays || []).slice().sort((a, b) => b.date.localeCompare(a.date)),
+    [allDays],
+  )
+
+  const selectedDay = useMemo(() => {
+    if (!selectedDateStr) return allDaysSorted[0] || null
+    return allDaysSorted.find(d => d.date === selectedDateStr) || null
+  }, [selectedDateStr, allDaysSorted])
+
+  const selectedIdx = useMemo(() => {
+    if (!selectedDay) return -1
+    return allDaysSorted.findIndex(d => d.date === selectedDay.date)
+  }, [selectedDay, allDaysSorted])
+
+  const handleDayClick = (dateStr) => setSelectedDateStr(d10(dateStr))
+  const goOlder = () => {
+    if (selectedIdx < allDaysSorted.length - 1)
+      setSelectedDateStr(allDaysSorted[selectedIdx + 1].date)
+  }
+  const goNewer = () => {
+    if (selectedIdx > 0)
+      setSelectedDateStr(allDaysSorted[selectedIdx - 1].date)
+  }
+
+  // The date string to highlight in charts (only shown if it falls within the current trend window)
+  const selDateForCharts = selectedDay?.date
 
   return (
     <div className="p-6 space-y-8">
       <h1 className="text-2xl font-bold text-white">Health</h1>
 
-      {/* Daily snapshot */}
+      <DailySnapshot
-      <DailySnapshot latest={latest} avg30={avg30} />
+        day={selectedDay}
+        avg30={summary?.avg_30d}
+        onOlder={goOlder}
+        onNewer={goNewer}
+        hasOlder={selectedIdx >= 0 && selectedIdx < allDaysSorted.length - 1}
+        hasNewer={selectedIdx > 0}
+      />
 
-      {/* Divider */}
       <div className="border-t border-gray-800" />
 
-      {/* Trends section */}
       <div className="space-y-4">
-        <div className="flex items-center justify-between">
+        <div className="flex items-center justify-between flex-wrap gap-2">
+          <div>
             <h2 className="text-base font-semibold text-gray-300">Trends</h2>
+            <p className="text-xs text-gray-600">Click any point to load that day above</p>
+          </div>
           <div className="flex gap-1.5">
             {RANGES.map(({ label, days }) => (
               <button key={label} onClick={() => setRangeDays(days)}
@@ -404,24 +463,27 @@ export default function HealthPage() {
 
         {isLoading ? (
           <div className="text-gray-500 text-sm">Loading…</div>
-        ) : metrics && metrics.length > 0 ? (
+        ) : metrics.length > 0 ? (
           <div className="grid grid-cols-1 lg:grid-cols-2 gap-4">
 
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">Resting Heart Rate</h3>
               <MetricChart data={metrics} dataKey="resting_hr" color="#f43f5e"
-                formatter={v => `${Math.round(v)} bpm`} />
+                formatter={v => `${Math.round(v)} bpm`}
+                selectedDate={selDateForCharts} onDayClick={handleDayClick} />
             </div>
 
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">HRV (nightly avg)</h3>
               <MetricChart data={metrics} dataKey="hrv_nightly_avg" color="#8b5cf6"
-                formatter={v => `${Math.round(v)} ms`} />
+                formatter={v => `${Math.round(v)} ms`}
+                selectedDate={selDateForCharts} onDayClick={handleDayClick} />
             </div>
 
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">Sleep</h3>
-              <SleepChart data={metrics} />
+              <SleepChart data={metrics}
+                selectedDate={selDateForCharts} onDayClick={handleDayClick} />
               <div className="flex gap-4 mt-2">
                 {[['Deep','#6366f1'],['REM','#8b5cf6'],['Light','#a78bfa'],['Awake','#374151']].map(([l,c]) => (
                   <div key={l} className="flex items-center gap-1.5">
@@ -435,19 +497,32 @@ export default function HealthPage() {
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">Weight</h3>
               <MetricChart data={metrics} dataKey="weight_kg" color="#34d399"
-                formatter={v => `${v.toFixed(1)} kg`} />
+                formatter={v => `${v.toFixed(1)} kg`}
+                selectedDate={selDateForCharts} onDayClick={handleDayClick} />
             </div>
 
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">Daily Steps</h3>
               <ResponsiveContainer width="100%" height={140}>
-                <BarChart data={metrics} margin={{ top: 4, right: 4, bottom: 4, left: 0 }} barSize={6}>
+                <BarChart
+                  data={metrics}
+                  margin={{ top: 4, right: 4, bottom: 4, left: 0 }}
+                  barSize={6}
+                  style={{ cursor: 'pointer' }}
+                  onClick={evt => {
+                    const p = evt?.activePayload?.[0]?.payload
+                    if (p?.date) handleDayClick(p.date)
+                  }}
+                >
                   <CartesianGrid strokeDasharray="3 3" stroke="#1f2937" vertical={false} />
                   <XAxis dataKey="date" tick={{ fontSize: 10, fill: '#6b7280' }} axisLine={false} tickLine={false}
                     tickFormatter={d => format(new Date(d), 'MMM d')} interval="preserveStartEnd" />
                   <YAxis tick={{ fontSize: 10, fill: '#6b7280' }} axisLine={false} tickLine={false} width={36}
                     tickFormatter={v => v >= 1000 ? `${(v/1000).toFixed(0)}k` : v} />
                   <Tooltip contentStyle={tooltipStyle} labelFormatter={d => format(new Date(d), 'MMM d, yyyy')} />
+                  {selDateForCharts && (
+                    <ReferenceLine x={selDateForCharts} stroke="#60a5fa" strokeWidth={1.5} strokeDasharray="4 2" />
+                  )}
                   <Bar dataKey="steps" name="Steps" fill="#fbbf24" radius={[2, 2, 0, 0]} isAnimationActive={false} />
                 </BarChart>
               </ResponsiveContainer>
@@ -456,19 +531,23 @@ export default function HealthPage() {
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">Stress Level</h3>
               <MetricChart data={metrics} dataKey="avg_stress" color="#a78bfa"
-                formatter={v => Math.round(v)} />
+                formatter={v => Math.round(v)}
+                selectedDate={selDateForCharts} onDayClick={handleDayClick} />
             </div>
 
             <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
               <h3 className="text-sm font-medium text-gray-300 mb-3">Avg Heart Rate (day)</h3>
               <MetricChart data={metrics} dataKey="avg_hr_day" color="#f97316"
-                formatter={v => `${Math.round(v)} bpm`} />
+                formatter={v => `${Math.round(v)} bpm`}
+                selectedDate={selDateForCharts} onDayClick={handleDayClick} />
             </div>
 
             {metrics.some(d => d.vo2max) && (
               <div className="bg-gray-900 rounded-xl border border-gray-800 p-4">
                 <h3 className="text-sm font-medium text-gray-300 mb-3">VO2 Max</h3>
-                <MetricChart data={metrics} dataKey="vo2max" color="#3b82f6" formatter={v => v.toFixed(1)} />
+                <MetricChart data={metrics} dataKey="vo2max" color="#3b82f6"
+                  formatter={v => v.toFixed(1)}
+                  selectedDate={selDateForCharts} onDayClick={handleDayClick} />
               </div>
             )}