diff --git a/client/src/pages/BreedingCalendar.jsx b/client/src/pages/BreedingCalendar.jsx
index 17c08bb..ccd33c0 100644
--- a/client/src/pages/BreedingCalendar.jsx
+++ b/client/src/pages/BreedingCalendar.jsx
@@ -1,67 +1,529 @@
-import { useEffect, useState } from 'react'
-import { Heart } from 'lucide-react'
-import axios from 'axios'
+import { useEffect, useState, useCallback } from 'react'
+import {
+  Heart, ChevronLeft, ChevronRight, Plus, X,
+  CalendarDays, FlaskConical, Baby, AlertCircle, CheckCircle2
+} from 'lucide-react'
 
-function BreedingCalendar() {
-  const [heatCycles, setHeatCycles] = useState([])
-  const [loading, setLoading] = useState(true)
+// ─── Date helpers ────────────────────────────────────────────────────────────
+const toISO = d => d.toISOString().split('T')[0]
+const addDays = (dateStr, n) => {
+  const d = new Date(dateStr); d.setDate(d.getDate() + n); return toISO(d)
+}
+const fmt = str => str ? new Date(str + 'T00:00:00').toLocaleDateString('en-US', { month: 'short', day: 'numeric', year: 'numeric' }) : '—'
+const today = toISO(new Date())
 
-  useEffect(() => {
-    fetchHeatCycles()
-  }, [])
+// ─── Cycle window classifier ─────────────────────────────────────────────────
+function getWindowForDate(cycle, dateStr) {
+  if (!cycle?.start_date) return null
+  const start = new Date(cycle.start_date + 'T00:00:00')
+  const check = new Date(dateStr + 'T00:00:00')
+  const day = Math.round((check - start) / 86400000)
+  if (day < 0 || day > 28) return null
+  if (day <= 8)  return 'proestrus'
+  if (day <= 15) return 'optimal'
+  if (day <= 21) return 'late'
+  return 'diestrus'
+}
 
-  const fetchHeatCycles = async () => {
+const WINDOW_STYLES = {
+  proestrus: { bg: 'rgba(244,114,182,0.18)', border: '#f472b6', label: 'Proestrus', dot: '#f472b6' },
+  optimal:   { bg: 'rgba(16,185,129,0.22)',  border: '#10b981', label: 'Optimal Breeding', dot: '#10b981' },
+  late:      { bg: 'rgba(245,158,11,0.18)',  border: '#f59e0b', label: 'Late Estrus', dot: '#f59e0b' },
+  diestrus:  { bg: 'rgba(148,163,184,0.12)', border: '#64748b', label: 'Diestrus', dot: '#64748b' },
+}
+
+// ─── Start Heat Cycle Modal ───────────────────────────────────────────────────
+function StartCycleModal({ females, onClose, onSaved }) {
+  const [dogId, setDogId] = useState('')
+  const [startDate, setStartDate] = useState(today)
+  const [notes, setNotes] = useState('')
+  const [saving, setSaving] = useState(false)
+  const [error, setError] = useState(null)
+
+  async function handleSubmit(e) {
+    e.preventDefault()
+    if (!dogId || !startDate) return
+    setSaving(true); setError(null)
     try {
-      const res = await axios.get('/api/breeding/heat-cycles/active')
-      setHeatCycles(res.data)
-      setLoading(false)
-    } catch (error) {
-      console.error('Error fetching heat cycles:', error)
-      setLoading(false)
+      const res = await fetch('/api/breeding/heat-cycles', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ dog_id: parseInt(dogId), start_date: startDate, notes: notes || null })
+      })
+      if (!res.ok) { const e = await res.json(); throw new Error(e.error || 'Failed to save') }
+      onSaved()
+    } catch (err) {
+      setError(err.message)
+      setSaving(false)
     }
   }
 
-  if (loading) {
-    return <div className="container loading">Loading breeding calendar...</div>
-  }
-
   return (
-    <div className="container">
-      <h1 style={{ marginBottom: '2rem' }}>Breeding Calendar</h1>
-
-      <div className="card" style={{ marginBottom: '2rem' }}>
-        <h2>Active Heat Cycles</h2>
-        {heatCycles.length === 0 ? (
-          <div style={{ textAlign: 'center', padding: '2rem' }}>
-            <Heart size={48} style={{ color: 'var(--text-secondary)', margin: '0 auto 1rem' }} />
-            <p style={{ color: 'var(--text-secondary)' }}>No active heat cycles</p>
+    <div className="modal-overlay" onClick={e => e.target === e.currentTarget && onClose()}>
+      <div className="modal-content" style={{ maxWidth: '480px' }}>
+        <div className="modal-header">
+          <div style={{ display: 'flex', alignItems: 'center', gap: '0.6rem' }}>
+            <Heart size={18} style={{ color: '#f472b6' }} />
+            <h2>Start Heat Cycle</h2>
           </div>
-        ) : (
-          <div style={{ display: 'grid', gap: '1rem', marginTop: '1rem' }}>
-            {heatCycles.map(cycle => (
-              <div key={cycle.id} className="card" style={{ background: 'var(--bg-secondary)' }}>
-                <h3>{cycle.dog_name}</h3>
-                <p style={{ color: 'var(--text-secondary)' }}>
-                  Started: {new Date(cycle.start_date).toLocaleDateString()}
-                </p>
-                {cycle.registration_number && (
-                  <p style={{ fontSize: '0.875rem', color: 'var(--text-secondary)' }}>
-                    Reg: {cycle.registration_number}
-                  </p>
-                )}
-              </div>
-            ))}
+          <button className="btn-icon" onClick={onClose}><X size={20} /></button>
+        </div>
+        <form onSubmit={handleSubmit}>
+          <div className="modal-body">
+            {error && <div className="error" style={{ marginBottom: '1rem' }}>{error}</div>}
+            <div className="form-group">
+              <label className="label">Female Dog *</label>
+              <select value={dogId} onChange={e => setDogId(e.target.value)} required>
+                <option value="">— Select Female —</option>
+                {females.map(d => (
+                  <option key={d.id} value={d.id}>
+                    {d.name}{d.breed ? ` · ${d.breed}` : ''}
+                  </option>
+                ))}
+              </select>
+              {females.length === 0 && <p style={{ color: 'var(--text-muted)', fontSize: '0.8rem', marginTop: '0.4rem' }}>No female dogs registered.</p>}
+            </div>
+            <div className="form-group">
+              <label className="label">Heat Start Date *</label>
+              <input type="date" className="input" value={startDate} onChange={e => setStartDate(e.target.value)} required />
+            </div>
+            <div className="form-group" style={{ marginBottom: 0 }}>
+              <label className="label">Notes</label>
+              <textarea className="input" value={notes} onChange={e => setNotes(e.target.value)} placeholder="Optional notes..." rows={3} />
+            </div>
           </div>
-        )}
-      </div>
-
-      <div className="card">
-        <h2>Whelping Calculator</h2>
-        <p style={{ color: 'var(--text-secondary)', marginTop: '0.5rem' }}>Calculate expected whelping dates based on breeding dates</p>
-        <p style={{ marginTop: '1rem', fontSize: '0.875rem' }}>Feature coming soon...</p>
+          <div className="modal-footer">
+            <button type="button" className="btn btn-secondary" onClick={onClose}>Cancel</button>
+            <button type="submit" className="btn btn-primary" disabled={saving || !dogId}>
+              {saving ? 'Saving…' : <><Heart size={15} /> Start Cycle</>}
+            </button>
+          </div>
+        </form>
       </div>
     </div>
   )
 }
 
-export default BreedingCalendar
\ No newline at end of file
+// ─── Cycle Detail Modal ───────────────────────────────────────────────────────
+function CycleDetailModal({ cycle, onClose, onDeleted }) {
+  const [suggestions, setSuggestions] = useState(null)
+  const [breedingDate, setBreedingDate] = useState(cycle.breeding_date || '')
+  const [savingBreed, setSavingBreed] = useState(false)
+  const [deleting, setDeleting] = useState(false)
+  const [error, setError] = useState(null)
+
+  useEffect(() => {
+    fetch(`/api/breeding/heat-cycles/${cycle.id}/suggestions`)
+      .then(r => r.json())
+      .then(setSuggestions)
+      .catch(() => {})
+  }, [cycle.id])
+
+  async function saveBreedingDate() {
+    if (!breedingDate) return
+    setSavingBreed(true); setError(null)
+    try {
+      const res = await fetch(`/api/breeding/heat-cycles/${cycle.id}`, {
+        method: 'PUT',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ ...cycle, breeding_date: breedingDate })
+      })
+      if (!res.ok) { const e = await res.json(); throw new Error(e.error) }
+      // Refresh suggestions
+      const s = await fetch(`/api/breeding/heat-cycles/${cycle.id}/suggestions`).then(r => r.json())
+      setSuggestions(s)
+    } catch (err) { setError(err.message) }
+    finally { setSavingBreed(false) }
+  }
+
+  async function deleteCycle() {
+    if (!window.confirm(`Delete heat cycle for ${cycle.dog_name}? This cannot be undone.`)) return
+    setDeleting(true)
+    try {
+      await fetch(`/api/breeding/heat-cycles/${cycle.id}`, { method: 'DELETE' })
+      onDeleted()
+    } catch (err) { setError(err.message); setDeleting(false) }
+  }
+
+  const whelp = suggestions?.whelping
+
+  return (
+    <div className="modal-overlay" onClick={e => e.target === e.currentTarget && onClose()}>
+      <div className="modal-content" style={{ maxWidth: '560px' }}>
+        <div className="modal-header">
+          <div style={{ display: 'flex', alignItems: 'center', gap: '0.6rem' }}>
+            <Heart size={18} style={{ color: '#f472b6' }} />
+            <h2>{cycle.dog_name}</h2>
+          </div>
+          <button className="btn-icon" onClick={onClose}><X size={20} /></button>
+        </div>
+        <div className="modal-body">
+          {error && <div className="error">{error}</div>}
+
+          {/* Cycle meta */}
+          <div style={{ display: 'flex', gap: '1rem', marginBottom: '1.5rem', flexWrap: 'wrap' }}>
+            <div style={infoChip}>
+              <span style={{ color: 'var(--text-muted)', fontSize: '0.75rem', textTransform: 'uppercase', letterSpacing: '0.05em' }}>Started</span>
+              <span style={{ fontWeight: 600 }}>{fmt(cycle.start_date)}</span>
+            </div>
+            {cycle.breed && (
+              <div style={infoChip}>
+                <span style={{ color: 'var(--text-muted)', fontSize: '0.75rem', textTransform: 'uppercase', letterSpacing: '0.05em' }}>Breed</span>
+                <span style={{ fontWeight: 600 }}>{cycle.breed}</span>
+              </div>
+            )}
+          </div>
+
+          {/* Breeding date windows */}
+          {suggestions && (
+            <>
+              <h3 style={{ fontSize: '0.9375rem', marginBottom: '0.75rem', display: 'flex', alignItems: 'center', gap: '0.4rem' }}>
+                <FlaskConical size={16} style={{ color: 'var(--accent)' }} /> Breeding Date Windows
+              </h3>
+              <div style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem', marginBottom: '1.5rem' }}>
+                {suggestions.windows.map(w => (
+                  <div key={w.type} style={{
+                    display: 'flex', alignItems: 'flex-start', gap: '0.75rem',
+                    padding: '0.625rem 0.875rem',
+                    background: WINDOW_STYLES[w.type]?.bg,
+                    border: `1px solid ${WINDOW_STYLES[w.type]?.border}`,
+                    borderRadius: 'var(--radius-sm)'
+                  }}>
+                    <div style={{ width: 10, height: 10, borderRadius: '50%', background: WINDOW_STYLES[w.type]?.dot, marginTop: 4, flexShrink: 0 }} />
+                    <div style={{ flex: 1, minWidth: 0 }}>
+                      <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', gap: '0.5rem', flexWrap: 'wrap' }}>
+                        <span style={{ fontWeight: 600, fontSize: '0.875rem' }}>{w.label}</span>
+                        <span style={{ fontSize: '0.8125rem', color: 'var(--text-secondary)', whiteSpace: 'nowrap' }}>{fmt(w.start)} – {fmt(w.end)}</span>
+                      </div>
+                      <p style={{ fontSize: '0.8rem', color: 'var(--text-muted)', margin: '0.15rem 0 0' }}>{w.description}</p>
+                    </div>
+                  </div>
+                ))}
+              </div>
+            </>
+          )}
+
+          {/* Log breeding date */}
+          <div style={{ background: 'var(--bg-tertiary)', borderRadius: 'var(--radius)', padding: '1rem', marginBottom: '1.25rem' }}>
+            <h3 style={{ fontSize: '0.9375rem', marginBottom: '0.75rem', display: 'flex', alignItems: 'center', gap: '0.4rem' }}>
+              <CalendarDays size={16} style={{ color: 'var(--primary)' }} /> Log Breeding Date
+            </h3>
+            <div style={{ display: 'flex', gap: '0.75rem', alignItems: 'flex-end', flexWrap: 'wrap' }}>
+              <div style={{ flex: 1, minWidth: 160 }}>
+                <label className="label" style={{ marginBottom: '0.4rem' }}>Breeding Date</label>
+                <input type="date" className="input" value={breedingDate} onChange={e => setBreedingDate(e.target.value)} />
+              </div>
+              <button className="btn btn-primary" onClick={saveBreedingDate} disabled={savingBreed || !breedingDate} style={{ marginBottom: 0 }}>
+                {savingBreed ? 'Saving…' : 'Save'}
+              </button>
+            </div>
+          </div>
+
+          {/* Whelping estimate */}
+          {whelp && (
+            <div style={{ background: 'rgba(16,185,129,0.08)', border: '1px solid rgba(16,185,129,0.3)', borderRadius: 'var(--radius)', padding: '1rem' }}>
+              <h3 style={{ fontSize: '0.9375rem', marginBottom: '0.75rem', display: 'flex', alignItems: 'center', gap: '0.4rem', color: 'var(--success)' }}>
+                <Baby size={16} /> Whelping Estimate
+              </h3>
+              <div style={{ display: 'grid', gridTemplateColumns: 'repeat(3, 1fr)', gap: '0.75rem', textAlign: 'center' }}>
+                {[['Earliest', whelp.earliest], ['Expected', whelp.expected], ['Latest', whelp.latest]].map(([label, date]) => (
+                  <div key={label}>
+                    <div style={{ fontSize: '0.75rem', color: 'var(--text-muted)', textTransform: 'uppercase', letterSpacing: '0.05em', marginBottom: '0.2rem' }}>{label}</div>
+                    <div style={{ fontWeight: 700, fontSize: '0.9375rem' }}>{fmt(date)}</div>
+                  </div>
+                ))}
+              </div>
+            </div>
+          )}
+        </div>
+        <div className="modal-footer" style={{ justifyContent: 'space-between' }}>
+          <button className="btn btn-danger" onClick={deleteCycle} disabled={deleting}>
+            {deleting ? 'Deleting…' : 'Delete Cycle'}
+          </button>
+          <button className="btn btn-secondary" onClick={onClose}>Close</button>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+const infoChip = {
+  display: 'flex', flexDirection: 'column', gap: '0.15rem',
+  padding: '0.5rem 0.875rem',
+  background: 'var(--bg-tertiary)',
+  borderRadius: 'var(--radius-sm)'
+}
+
+// ─── Main Calendar ────────────────────────────────────────────────────────────
+export default function BreedingCalendar() {
+  const now = new Date()
+  const [year, setYear] = useState(now.getFullYear())
+  const [month, setMonth] = useState(now.getMonth()) // 0-indexed
+  const [cycles, setCycles] = useState([])
+  const [females, setFemales] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showStartModal, setShowStartModal] = useState(false)
+  const [selectedCycle, setSelectedCycle] = useState(null)
+  const [selectedDay, setSelectedDay] = useState(null)
+
+  const load = useCallback(async () => {
+    setLoading(true)
+    try {
+      const [cyclesRes, dogsRes] = await Promise.all([
+        fetch('/api/breeding/heat-cycles'),
+        fetch('/api/dogs')
+      ])
+      const allCycles = await cyclesRes.json()
+      const dogsData = await dogsRes.json()
+      const allDogs = Array.isArray(dogsData) ? dogsData : (dogsData.dogs || [])
+      setCycles(Array.isArray(allCycles) ? allCycles : [])
+      setFemales(allDogs.filter(d => d.sex === 'female'))
+    } catch (e) {
+      console.error(e)
+    } finally {
+      setLoading(false)
+    }
+  }, [])
+
+  useEffect(() => { load() }, [load])
+
+  // ── Build calendar grid ──
+  const firstDay = new Date(year, month, 1)
+  const lastDay = new Date(year, month + 1, 0)
+  const startPad = firstDay.getDay() // 0=Sun
+  const totalCells = startPad + lastDay.getDate()
+  const rows = Math.ceil(totalCells / 7)
+
+  const MONTH_NAMES = ['January','February','March','April','May','June','July','August','September','October','November','December']
+  const DAY_NAMES = ['Sun','Mon','Tue','Wed','Thu','Fri','Sat']
+
+  function prevMonth() {
+    if (month === 0) { setMonth(11); setYear(y => y - 1) }
+    else setMonth(m => m - 1)
+  }
+  function nextMonth() {
+    if (month === 11) { setMonth(0); setYear(y => y + 1) }
+    else setMonth(m => m + 1)
+  }
+
+  // Find cycles that overlap a given date
+  function cyclesForDate(dateStr) {
+    return cycles.filter(c => {
+      const s = c.start_date
+      if (!s) return false
+      const end = c.end_date || addDays(s, 28)
+      return dateStr >= s && dateStr <= end
+    })
+  }
+
+  function handleDayClick(dateStr, dayCycles) {
+    setSelectedDay(dateStr)
+    if (dayCycles.length === 1) {
+      setSelectedCycle(dayCycles[0])
+    } else if (dayCycles.length > 1) {
+      // show first — could be upgraded to a picker
+      setSelectedCycle(dayCycles[0])
+    } else {
+      // Empty day click — open start modal with date pre-filled would be nice
+      // but we just open start modal; user picks date
+      setShowStartModal(true)
+    }
+  }
+
+  // Active cycles (in current month or ongoing)
+  const activeCycles = cycles.filter(c => {
+    const s = c.start_date; if (!s) return false
+    const end = c.end_date || addDays(s, 28)
+    const mStart = toISO(new Date(year, month, 1))
+    const mEnd = toISO(new Date(year, month + 1, 0))
+    return s <= mEnd && end >= mStart
+  })
+
+  return (
+    <div className="container" style={{ paddingTop: '2rem', paddingBottom: '3rem' }}>
+      {/* Header */}
+      <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: '1.5rem', flexWrap: 'wrap', gap: '1rem' }}>
+        <div style={{ display: 'flex', alignItems: 'center', gap: '0.75rem' }}>
+          <div style={{ width: '2.5rem', height: '2.5rem', borderRadius: 'var(--radius)', background: 'rgba(244,114,182,0.2)', display: 'flex', alignItems: 'center', justifyContent: 'center', color: '#f472b6' }}>
+            <Heart size={20} />
+          </div>
+          <div>
+            <h1 style={{ fontSize: '1.75rem', margin: 0 }}>Heat Cycle Calendar</h1>
+            <p style={{ color: 'var(--text-muted)', margin: 0, fontSize: '0.875rem' }}>Track heat cycles and optimal breeding windows</p>
+          </div>
+        </div>
+        <button className="btn btn-primary" onClick={() => setShowStartModal(true)}>
+          <Plus size={16} /> Start Heat Cycle
+        </button>
+      </div>
+
+      {/* Legend */}
+      <div style={{ display: 'flex', gap: '0.75rem', marginBottom: '1.25rem', flexWrap: 'wrap' }}>
+        {Object.entries(WINDOW_STYLES).map(([key, s]) => (
+          <div key={key} style={{ display: 'flex', alignItems: 'center', gap: '0.4rem', fontSize: '0.8125rem', color: 'var(--text-secondary)' }}>
+            <div style={{ width: 10, height: 10, borderRadius: '50%', background: s.dot }} />
+            {s.label}
+          </div>
+        ))}
+      </div>
+
+      {/* Month navigator */}
+      <div className="card" style={{ marginBottom: '1rem', padding: '0' }}>
+        <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '0.875rem 1rem', borderBottom: '1px solid var(--border)' }}>
+          <button className="btn-icon" onClick={prevMonth}><ChevronLeft size={20} /></button>
+          <h2 style={{ margin: 0, fontSize: '1.1rem' }}>{MONTH_NAMES[month]} {year}</h2>
+          <button className="btn-icon" onClick={nextMonth}><ChevronRight size={20} /></button>
+        </div>
+
+        {/* Day headers */}
+        <div style={{ display: 'grid', gridTemplateColumns: 'repeat(7, 1fr)', borderBottom: '1px solid var(--border)' }}>
+          {DAY_NAMES.map(d => (
+            <div key={d} style={{ padding: '0.5rem', textAlign: 'center', fontSize: '0.75rem', fontWeight: 600, color: 'var(--text-muted)', textTransform: 'uppercase', letterSpacing: '0.05em' }}>{d}</div>
+          ))}
+        </div>
+
+        {/* Calendar cells */}
+        {loading ? (
+          <div className="loading" style={{ minHeight: 280 }}>Loading calendar…</div>
+        ) : (
+          <div style={{ display: 'grid', gridTemplateColumns: 'repeat(7, 1fr)' }}>
+            {Array.from({ length: rows * 7 }).map((_, idx) => {
+              const dayNum = idx - startPad + 1
+              const isValid = dayNum >= 1 && dayNum <= lastDay.getDate()
+              const dateStr = isValid ? toISO(new Date(year, month, dayNum)) : null
+              const dayCycles = dateStr ? cyclesForDate(dateStr) : []
+              const isToday = dateStr === today
+
+              // Pick dominant window color for background
+              let cellBg = 'transparent'
+              let cellBorder = 'var(--border)'
+              if (dayCycles.length > 0) {
+                const win = getWindowForDate(dayCycles[0], dateStr)
+                if (win && WINDOW_STYLES[win]) {
+                  cellBg = WINDOW_STYLES[win].bg
+                  cellBorder = WINDOW_STYLES[win].border
+                }
+              }
+
+              return (
+                <div
+                  key={idx}
+                  onClick={() => isValid && handleDayClick(dateStr, dayCycles)}
+                  style={{
+                    minHeight: 72,
+                    padding: '0.375rem 0.5rem',
+                    borderRight: '1px solid var(--border)',
+                    borderBottom: '1px solid var(--border)',
+                    background: cellBg,
+                    cursor: isValid ? 'pointer' : 'default',
+                    position: 'relative',
+                    transition: 'filter 0.15s',
+                    opacity: isValid ? 1 : 0.3,
+                    outline: isToday ? `2px solid var(--primary)` : 'none',
+                    outlineOffset: -2,
+                  }}
+                  onMouseEnter={e => { if (isValid) e.currentTarget.style.filter = 'brightness(1.15)' }}
+                  onMouseLeave={e => { e.currentTarget.style.filter = 'none' }}
+                >
+                  {isValid && (
+                    <>
+                      <div style={{
+                        fontSize: '0.8125rem', fontWeight: isToday ? 700 : 500,
+                        color: isToday ? 'var(--primary)' : 'var(--text-primary)',
+                        marginBottom: '0.25rem'
+                      }}>{dayNum}</div>
+                      {dayCycles.map((c, i) => {
+                        const win = getWindowForDate(c, dateStr)
+                        const dot = win ? WINDOW_STYLES[win]?.dot : '#94a3b8'
+                        return (
+                          <div key={i} style={{
+                            fontSize: '0.7rem', color: dot, fontWeight: 600,
+                            whiteSpace: 'nowrap', overflow: 'hidden', textOverflow: 'ellipsis',
+                            lineHeight: 1.3
+                          }}>
+                            ♥ {c.dog_name}
+                          </div>
+                        )
+                      })}
+                      {/* Breeding date marker */}
+                      {dayCycles.some(c => c.breeding_date === dateStr) && (
+                        <div style={{ position: 'absolute', top: 4, right: 4, width: 8, height: 8, borderRadius: '50%', background: 'var(--success)', border: '1.5px solid var(--bg-primary)' }} title="Breeding date logged" />
+                      )}
+                    </>
+                  )}
+                </div>
+              )
+            })}
+          </div>
+        )}
+      </div>
+
+      {/* Active cycles list */}
+      <div style={{ marginTop: '1.5rem' }}>
+        <h3 style={{ fontSize: '1rem', marginBottom: '0.875rem', display: 'flex', alignItems: 'center', gap: '0.5rem' }}>
+          <AlertCircle size={16} style={{ color: '#f472b6' }} />
+          Active Cycles This Month
+          <span className="badge badge-primary">{activeCycles.length}</span>
+        </h3>
+        {activeCycles.length === 0 ? (
+          <div className="card" style={{ textAlign: 'center', padding: '2rem', color: 'var(--text-muted)' }}>
+            <Heart size={32} style={{ margin: '0 auto 0.75rem', opacity: 0.4 }} />
+            <p>No active heat cycles this month.</p>
+            <button className="btn btn-primary" style={{ marginTop: '1rem' }} onClick={() => setShowStartModal(true)}>
+              <Plus size={15} /> Start First Cycle
+            </button>
+          </div>
+        ) : (
+          <div style={{ display: 'grid', gap: '0.75rem', gridTemplateColumns: 'repeat(auto-fill, minmax(260px, 1fr))' }}>
+            {activeCycles.map(c => {
+              const win = getWindowForDate(c, today)
+              const ws = win ? WINDOW_STYLES[win] : null
+              const daysSince = Math.round((new Date(today) - new Date(c.start_date + 'T00:00:00')) / 86400000)
+              return (
+                <div
+                  key={c.id}
+                  className="card"
+                  style={{ cursor: 'pointer', borderColor: ws?.border || 'var(--border)', background: ws?.bg || 'var(--bg-secondary)' }}
+                  onClick={() => setSelectedCycle(c)}
+                >
+                  <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'flex-start' }}>
+                    <div>
+                      <h4 style={{ margin: '0 0 0.2rem', fontSize: '1rem' }}>{c.dog_name}</h4>
+                      {c.breed && <p style={{ color: 'var(--text-muted)', fontSize: '0.8rem', margin: 0 }}>{c.breed}</p>}
+                    </div>
+                    {ws && <span className="badge" style={{ background: ws.bg, color: ws.dot, border: `1px solid ${ws.border}`, flexShrink: 0 }}>{ws.label}</span>}
+                  </div>
+                  <div style={{ marginTop: '0.75rem', display: 'flex', gap: '1rem', fontSize: '0.8125rem', color: 'var(--text-secondary)' }}>
+                    <span>Started {fmt(c.start_date)}</span>
+                    <span>Day {daysSince + 1}</span>
+                  </div>
+                  {c.breeding_date && (
+                    <div style={{ marginTop: '0.5rem', display: 'flex', alignItems: 'center', gap: '0.4rem', fontSize: '0.8rem', color: 'var(--success)' }}>
+                      <CheckCircle2 size={13} /> Bred {fmt(c.breeding_date)}
+                    </div>
+                  )}
+                </div>
+              )
+            })}
+          </div>
+        )}
+      </div>
+
+      {/* Modals */}
+      {showStartModal && (
+        <StartCycleModal
+          females={females}
+          onClose={() => setShowStartModal(false)}
+          onSaved={() => { setShowStartModal(false); load() }}
+        />
+      )}
+      {selectedCycle && (
+        <CycleDetailModal
+          cycle={selectedCycle}
+          onClose={() => setSelectedCycle(null)}
+          onDeleted={() => { setSelectedCycle(null); load() }}
+        />
+      )}
+    </div>
+  )
+}
diff --git a/server/routes/breeding.js b/server/routes/breeding.js
index 0bec351..32efd36 100644
--- a/server/routes/breeding.js
+++ b/server/routes/breeding.js
@@ -11,55 +11,149 @@ router.get('/heat-cycles/dog/:dogId', (req, res) => {
       WHERE dog_id = ? 
       ORDER BY start_date DESC
     `).all(req.params.dogId);
-    
     res.json(cycles);
   } catch (error) {
     res.status(500).json({ error: error.message });
   }
 });
 
-// GET all active heat cycles
+// GET all active heat cycles (with dog info)
 router.get('/heat-cycles/active', (req, res) => {
   try {
     const db = getDatabase();
     const cycles = db.prepare(`
-      SELECT hc.*, d.name as dog_name, d.registration_number
+      SELECT hc.*, d.name as dog_name, d.registration_number, d.breed, d.birth_date
       FROM heat_cycles hc
       JOIN dogs d ON hc.dog_id = d.id
       WHERE hc.end_date IS NULL OR hc.end_date >= date('now', '-30 days')
       ORDER BY hc.start_date DESC
     `).all();
-    
     res.json(cycles);
   } catch (error) {
     res.status(500).json({ error: error.message });
   }
 });
 
+// GET all heat cycles (all dogs, for calendar population)
+router.get('/heat-cycles', (req, res) => {
+  try {
+    const db = getDatabase();
+    const { year, month } = req.query;
+    let query = `
+      SELECT hc.*, d.name as dog_name, d.registration_number, d.breed
+      FROM heat_cycles hc
+      JOIN dogs d ON hc.dog_id = d.id
+    `;
+    const params = [];
+    if (year && month) {
+      query += ` WHERE strftime('%Y', hc.start_date) = ? AND strftime('%m', hc.start_date) = ?`;
+      params.push(year, month.toString().padStart(2, '0'));
+    }
+    query += ' ORDER BY hc.start_date DESC';
+    const cycles = db.prepare(query).all(...params);
+    res.json(cycles);
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// GET breeding date suggestions for a heat cycle
+// Returns optimal breeding window based on start_date (days 9-15 of cycle)
+router.get('/heat-cycles/:id/suggestions', (req, res) => {
+  try {
+    const db = getDatabase();
+    const cycle = db.prepare(`
+      SELECT hc.*, d.name as dog_name
+      FROM heat_cycles hc
+      JOIN dogs d ON hc.dog_id = d.id
+      WHERE hc.id = ?
+    `).get(req.params.id);
+
+    if (!cycle) return res.status(404).json({ error: 'Heat cycle not found' });
+
+    const start = new Date(cycle.start_date);
+
+    const addDays = (d, n) => {
+      const r = new Date(d);
+      r.setDate(r.getDate() + n);
+      return r.toISOString().split('T')[0];
+    };
+
+    // Standard canine heat cycle windows
+    res.json({
+      cycle_id: cycle.id,
+      dog_name: cycle.dog_name,
+      start_date: cycle.start_date,
+      windows: [
+        {
+          label: 'Proestrus',
+          description: 'Bleeding begins, not yet receptive',
+          start: addDays(start, 0),
+          end: addDays(start, 8),
+          color: 'pink',
+          type: 'proestrus'
+        },
+        {
+          label: 'Optimal Breeding Window',
+          description: 'Estrus — highest fertility, best time to breed',
+          start: addDays(start, 9),
+          end: addDays(start, 15),
+          color: 'green',
+          type: 'optimal'
+        },
+        {
+          label: 'Late Estrus',
+          description: 'Fertility declining but breeding still possible',
+          start: addDays(start, 16),
+          end: addDays(start, 21),
+          color: 'yellow',
+          type: 'late'
+        },
+        {
+          label: 'Diestrus',
+          description: 'Cycle ending, not receptive',
+          start: addDays(start, 22),
+          end: addDays(start, 28),
+          color: 'gray',
+          type: 'diestrus'
+        }
+      ],
+      // If a breeding_date was logged, compute whelping estimate
+      whelping: cycle.breeding_date ? {
+        breeding_date: cycle.breeding_date,
+        earliest: addDays(new Date(cycle.breeding_date), 58),
+        expected: addDays(new Date(cycle.breeding_date), 63),
+        latest: addDays(new Date(cycle.breeding_date), 68)
+      } : null
+    });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
 // POST create heat cycle
 router.post('/heat-cycles', (req, res) => {
   try {
-    const { dog_id, start_date, end_date, progesterone_peak_date, breeding_date, breeding_successful, notes } = req.body;
-    
+    const { dog_id, start_date, end_date, breeding_date, breeding_successful, notes } = req.body;
+
     if (!dog_id || !start_date) {
       return res.status(400).json({ error: 'Dog ID and start date are required' });
     }
-    
+
     const db = getDatabase();
-    
+
     // Verify dog is female
     const dog = db.prepare('SELECT sex FROM dogs WHERE id = ?').get(dog_id);
     if (!dog || dog.sex !== 'female') {
       return res.status(400).json({ error: 'Dog must be female' });
     }
-    
+
     const result = db.prepare(`
-      INSERT INTO heat_cycles (dog_id, start_date, end_date, progesterone_peak_date, breeding_date, breeding_successful, notes)
-      VALUES (?, ?, ?, ?, ?, ?, ?)
-    `).run(dog_id, start_date, end_date, progesterone_peak_date, breeding_date, breeding_successful || 0, notes);
-    
+      INSERT INTO heat_cycles (dog_id, start_date, end_date, breeding_date, breeding_successful, notes)
+      VALUES (?, ?, ?, ?, ?, ?)
+    `).run(dog_id, start_date, end_date || null, breeding_date || null, breeding_successful || 0, notes || null);
+
     const cycle = db.prepare('SELECT * FROM heat_cycles WHERE id = ?').get(result.lastInsertRowid);
-    
     res.status(201).json(cycle);
   } catch (error) {
     res.status(500).json({ error: error.message });
@@ -69,16 +163,13 @@ router.post('/heat-cycles', (req, res) => {
 // PUT update heat cycle
 router.put('/heat-cycles/:id', (req, res) => {
   try {
-    const { start_date, end_date, progesterone_peak_date, breeding_date, breeding_successful, notes } = req.body;
-    
+    const { start_date, end_date, breeding_date, breeding_successful, notes } = req.body;
     const db = getDatabase();
     db.prepare(`
       UPDATE heat_cycles 
-      SET start_date = ?, end_date = ?, progesterone_peak_date = ?, 
-          breeding_date = ?, breeding_successful = ?, notes = ?
+      SET start_date = ?, end_date = ?, breeding_date = ?, breeding_successful = ?, notes = ?
       WHERE id = ?
-    `).run(start_date, end_date, progesterone_peak_date, breeding_date, breeding_successful, notes, req.params.id);
-    
+    `).run(start_date, end_date || null, breeding_date || null, breeding_successful || 0, notes || null, req.params.id);
     const cycle = db.prepare('SELECT * FROM heat_cycles WHERE id = ?').get(req.params.id);
     res.json(cycle);
   } catch (error) {
@@ -97,32 +188,20 @@ router.delete('/heat-cycles/:id', (req, res) => {
   }
 });
 
-// GET calculate expected whelping date
+// GET whelping calculator (standalone)
 router.get('/whelping-calculator', (req, res) => {
   try {
     const { breeding_date } = req.query;
-    
     if (!breeding_date) {
       return res.status(400).json({ error: 'Breeding date is required' });
     }
-    
     const breedDate = new Date(breeding_date);
-    
-    // Average gestation: 63 days, range 58-68 days
-    const expectedDate = new Date(breedDate);
-    expectedDate.setDate(expectedDate.getDate() + 63);
-    
-    const earliestDate = new Date(breedDate);
-    earliestDate.setDate(earliestDate.getDate() + 58);
-    
-    const latestDate = new Date(breedDate);
-    latestDate.setDate(latestDate.getDate() + 68);
-    
+    const addDays = (d, n) => { const r = new Date(d); r.setDate(r.getDate() + n); return r.toISOString().split('T')[0]; };
     res.json({
-      breeding_date: breeding_date,
-      expected_whelping_date: expectedDate.toISOString().split('T')[0],
-      earliest_date: earliestDate.toISOString().split('T')[0],
-      latest_date: latestDate.toISOString().split('T')[0],
+      breeding_date,
+      expected_whelping_date: addDays(breedDate, 63),
+      earliest_date: addDays(breedDate, 58),
+      latest_date: addDays(breedDate, 68),
       gestation_days: 63
     });
   } catch (error) {
@@ -130,4 +209,4 @@ router.get('/whelping-calculator', (req, res) => {
   }
 });
 
-module.exports = router;
\ No newline at end of file
+module.exports = router;