From 7fd139b32121a1aafd0a6ed2c107574afb6c8635 Mon Sep 17 00:00:00 2001
From: Dayowe <dayowe@tutamail.com>
Date: Wed, 12 Nov 2025 16:44:43 +0100
Subject: [PATCH] Kaya transition v1

---
 iframe.html          | 251 ++++++++++++++++++++++++-------------------
 src/css/main.css     |   6 ++
 src/index.html       |  80 ++------------
 src/js/calculator.js | 165 +++++++++++++++++++++-------
 4 files changed, 278 insertions(+), 224 deletions(-)

diff --git a/iframe.html b/iframe.html
index c38d605..33c89c7 100644
--- a/iframe.html
+++ b/iframe.html
@@ -200,6 +200,12 @@
             color: var(--text-label);
         }
 
+        /* Kaya end-weight readonly field: compact, non-editable */
+        #kayaEndWeight {
+            width: 120px;
+            display: inline-block;
+        }
+
         .dog-calculator-results {
             background: linear-gradient(135deg, rgba(241, 154, 95, 0.08) 0%, rgba(241, 154, 95, 0.04) 100%);
             border: 1px solid rgba(241, 154, 95, 0.2);
@@ -1964,50 +1970,18 @@
     <div class="dog-calculator-container" id="dogCalculator">
         <div class="dog-calculator-section">
             <div class="dog-calculator-section-header">
-                <h2>Dog's Characteristics</h2>
-                <div class="dog-calculator-unit-switch">
-                    <span class="dog-calculator-unit-label active" id="metricLabel">Metric</span>
-                    <label class="dog-calculator-switch">
-                        <input type="checkbox" id="unitToggle">
-                        <span class="dog-calculator-slider"></span>
-                    </label>
-                    <span class="dog-calculator-unit-label" id="imperialLabel">Imperial</span>
-                </div>
-            </div>
-            
-            <div class="dog-calculator-form-group">
-                <label for="dogType">Dog Type / Activity Level:</label>
-                <select id="dogType" aria-describedby="dogTypeHelp">
-                    <option value="">Select dog type...</option>
-                    <option value="3.0">Puppy (0-4 months)</option>
-                    <option value="2.0">Puppy (4 months - adult)</option>
-                    <option value="1.2">Adult - inactive/obese</option>
-                    <option value="1.6">Adult (neutered/spayed) - average activity</option>
-                    <option value="1.8">Adult (intact) - average activity</option>
-                    <option value="1.0">Adult - weight loss</option>
-                    <option value="1.7">Adult - weight gain</option>
-                    <option value="2.0">Working dog - light work</option>
-                    <option value="3.0">Working dog - moderate work</option>
-                    <option value="5.0">Working dog - heavy work</option>
-                    <option value="1.1">Senior dog</option>
-                </select>
+                <h2>Kaya’s Transition</h2>
             </div>
 
             <div class="dog-calculator-form-group">
-                <label for="weight" id="weightLabel">Dog's Weight (kg):</label>
-                <input type="number" id="weight" min="0.1" step="0.1" placeholder="Enter weight in kg" aria-describedby="weightHelp">
-                <div id="weightError" class="dog-calculator-error dog-calculator-hidden">Please enter a valid weight (minimum 0.1 kg)</div>
+                <label for="ageMonths">Kaya’s age (months):</label>
+                <input type="number" id="ageMonths" min="2" max="12" step="0.1" placeholder="Enter age in months" aria-describedby="ageHelp">
+                <div id="ageClampNote" class="dog-calculator-error dog-calculator-hidden">Age adjusted to the supported 2–12 month range.</div>
             </div>
 
-            <div class="dog-calculator-results" id="calorieResults" style="display: none;">
-                <div class="dog-calculator-result-item">
-                    <span class="dog-calculator-result-label">Resting Energy Requirement (RER):</span>
-                    <span class="dog-calculator-result-value" id="rerValue">- cal/day</span>
-                </div>
-                <div class="dog-calculator-result-item">
-                    <span class="dog-calculator-result-label">Maintenance Energy Requirement (MER):</span>
-                    <span class="dog-calculator-result-value" id="merValue">- cal/day</span>
-                </div>
+            <div class="dog-calculator-form-group">
+                <label for="kayaEndWeight">Kaya’s end‑weight:</label>
+                <input type="text" id="kayaEndWeight" value="30 kg" readonly>
             </div>
         </div>
 
@@ -2102,46 +2076,12 @@
             </div>
         </div>
 
-        <div class="dog-calculator-action-buttons">
-            <button class="dog-calculator-btn dog-calculator-btn-share" id="shareBtn">
-                Share
-            </button>
-        </div>
-
         <div class="dog-calculator-footer">
             <a href="https://caninenutritionandwellness.com" target="_blank" rel="noopener noreferrer">
                 by caninenutritionandwellness.com
             </a>
         </div>
-        <!-- Share Modal -->
-        <div id="shareModal" class="dog-calculator-modal" style="display: none;">
-            <div class="dog-calculator-modal-content">
-                <span class="dog-calculator-modal-close" id="shareModalClose">&times;</span>
-                <h3>Share Calculator</h3>
-                <div class="dog-calculator-share-buttons">
-                    <button class="dog-calculator-share-btn dog-calculator-share-facebook plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-facebook" id="shareFacebook">
-                        Facebook
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-twitter plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-twitter" id="shareTwitter">
-                        Twitter
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-linkedin plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-linkedin" id="shareLinkedIn">
-                        LinkedIn
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-email plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-email" id="shareEmail">
-                        Email
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-copy plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-copy-link" id="shareCopy">
-                        Copy Link
-                    </button>
-                </div>
-                <div class="dog-calculator-share-url">
-                    <input type="text" id="shareUrl" readonly>
-                </div>
-            </div>
-        </div>
 
-        
     </div>
     <script>
         /**
@@ -2173,6 +2113,9 @@ const CALCULATOR_CONFIG = {
                 this.maxFoodSources = CALCULATOR_CONFIG.maxFoodSources;
                 this.mealsPerDay = 2;
                 this.showPerMeal = false;
+                // Kayafied reference source tracking
+                this.kibbleRefId = null;
+                this.gcRefId = null;
                 this.init();
             }
 
@@ -2227,8 +2170,45 @@ const CALCULATOR_CONFIG = {
 
             // Food Source Management Methods
             initializeFoodSources() {
-                this.addFoodSource();
+                // Seed three sources for Kaya's transition
+                const gc = {
+                    id: this.generateFoodSourceId(),
+                    name: 'Fred & Felia, gently cooked',
+                    energy: '115',
+                    energyUnit: 'kcal100g',
+                    percentage: 5,
+                    isLocked: false
+                };
+                this.foodSources.push(gc);
+                this.renderFoodSource(gc);
+                this.gcRefId = gc.id;
+
+                const kibble = {
+                    id: this.generateFoodSourceId(),
+                    name: 'Eukanuba, kibble',
+                    energy: '372',
+                    energyUnit: 'kcal100g',
+                    percentage: 95,
+                    isLocked: false
+                };
+                this.foodSources.push(kibble);
+                this.renderFoodSource(kibble);
+                this.kibbleRefId = kibble.id;
+
+                const treats = {
+                    id: this.generateFoodSourceId(),
+                    name: 'Treats',
+                    energy: '',
+                    energyUnit: 'kcal100g',
+                    percentage: 0,
+                    isLocked: false
+                };
+                this.foodSources.push(treats);
+                this.renderFoodSource(treats);
+
                 this.updateAddButton();
+                this.updateRemoveButtons();
+                this.refreshAllPercentageUI();
             }
 
             addFoodSource() {
@@ -2263,6 +2243,9 @@ const CALCULATOR_CONFIG = {
                 if (index === -1) return;
 
                 this.foodSources.splice(index, 1);
+                // If reference IDs were removed, clear them
+                if (this.kibbleRefId === id) this.kibbleRefId = null;
+                if (this.gcRefId === id) this.gcRefId = null;
                 
                 // Remove the DOM element
                 const element = document.getElementById(`foodSource-${id}`);
@@ -2276,6 +2259,7 @@ const CALCULATOR_CONFIG = {
                 this.updateAddButton();
                 this.updateRemoveButtons();
                 this.refreshAllPercentageUI();
+                this.updateCalorieCalculations();
             }
 
             generateFoodSourceId() {
@@ -2747,6 +2731,10 @@ const CALCULATOR_CONFIG = {
                 if (energyInput) {
                     energyInput.addEventListener('input', () => {
                         this.updateFoodSourceData(id, 'energy', energyInput.value);
+                        // If kibble reference changed, recompute daily target
+                        if (id === this.kibbleRefId) {
+                            this.updateCalorieCalculations();
+                        }
                         
                         // Auto-select cups when entering energy for kcal/cup
                         const foodSource = this.foodSources.find(fs => fs.id === id);
@@ -2784,6 +2772,9 @@ const CALCULATOR_CONFIG = {
                 if (energyUnitSelect) {
                     energyUnitSelect.addEventListener('change', () => {
                         this.updateFoodSourceData(id, 'energyUnit', energyUnitSelect.value);
+                        if (id === this.kibbleRefId) {
+                            this.updateCalorieCalculations();
+                        }
                         
                         // Auto-select the most appropriate unit based on energy unit
                         const unitSelect = document.getElementById('unit');
@@ -2961,6 +2952,7 @@ const CALCULATOR_CONFIG = {
             bindEvents() {
                 const weightInput = document.getElementById('weight');
                 const dogTypeSelect = document.getElementById('dogType');
+                const ageInput = document.getElementById('ageMonths');
                 const daysInput = document.getElementById('days');
                 const unitSelect = document.getElementById('unit');
                 const unitToggle = document.getElementById('unitToggle');
@@ -2972,6 +2964,12 @@ const CALCULATOR_CONFIG = {
                 }
                 
                 if (dogTypeSelect) dogTypeSelect.addEventListener('change', () => this.updateCalorieCalculations());
+
+                // Kayafied: age input drives energy target
+                if (ageInput) {
+                    ageInput.addEventListener('input', () => this.updateCalorieCalculations());
+                    ageInput.addEventListener('blur', () => this.updateCalorieCalculations());
+                }
                 
                 if (daysInput) {
                     daysInput.addEventListener('input', () => {
@@ -3316,57 +3314,86 @@ const CALCULATOR_CONFIG = {
             }
 
             updateCalorieCalculations() {
-                const dogTypeSelect = document.getElementById('dogType');
-                const calorieResults = document.getElementById('calorieResults');
-                const rerValue = document.getElementById('rerValue');
-                const merValue = document.getElementById('merValue');
+                // Kaya-specific: compute daily kcal target from age + kibble energy
+                const ageInput = document.getElementById('ageMonths');
+                const ageClampNote = document.getElementById('ageClampNote');
 
-                if (!dogTypeSelect || !calorieResults || !rerValue || !merValue) {
+                // Default: hide clamp note
+                if (ageClampNote) ageClampNote.classList.add('dog-calculator-hidden');
+
+                if (!ageInput || !ageInput.value) {
+                    this.currentMER = 0;
+                    this.currentMERMin = 0;
+                    this.currentMERMax = 0;
                     return;
                 }
 
-                const weightKg = this.getWeightInKg();
-                const dogTypeFactor = dogTypeSelect.value;
-                
-                this.showError('weightError', false);
-                
-                if (!weightKg || weightKg < 0.1) {
-                    const weightInput = document.getElementById('weight');
-                    if (weightInput && weightInput.value) this.showError('weightError', true);
-                    calorieResults.style.display = 'none';
+                let age = parseFloat(ageInput.value);
+                if (isNaN(age)) {
+                    this.currentMER = 0;
+                    this.currentMERMin = 0;
+                    this.currentMERMax = 0;
                     return;
                 }
 
-                if (!dogTypeFactor) {
-                    calorieResults.style.display = 'none';
+                // Clamp age to [2, 12]
+                if (age < 2) { age = 2; if (ageClampNote) ageClampNote.classList.remove('dog-calculator-hidden'); }
+                if (age > 12) { age = 12; if (ageClampNote) ageClampNote.classList.remove('dog-calculator-hidden'); }
+
+                // Calculate interpolated kibble grams/day for 30 kg at this age
+                const kibbleGrams = this.getKayaKibbleGramsForAge(age);
+
+                // Get kibble reference energy density in kcal/100g
+                let kibbleEnergyPer100g = null;
+                if (this.kibbleRefId) {
+                    const kibbleRef = this.foodSources.find(fs => fs.id === this.kibbleRefId);
+                    kibbleEnergyPer100g = kibbleRef ? this.getFoodSourceEnergyPer100g(kibbleRef) : null;
+                }
+
+                if (!kibbleEnergyPer100g || kibbleEnergyPer100g <= 0) {
+                    // Cannot compute without kibble energy density
+                    this.currentMER = 0;
+                    this.currentMERMin = 0;
+                    this.currentMERMax = 0;
                     return;
                 }
 
-                const factor = parseFloat(dogTypeFactor);
-                
-                const rer = this.calculateRER(weightKg);
-                const mer = this.calculateMER(rer, factor);
-                
-                // Calculate range for MER
-                const range = this.getLifeStageRange(factor);
-                this.currentMERMin = this.calculateMER(rer, range.min);
-                this.currentMERMax = this.calculateMER(rer, range.max);
-                this.currentMER = mer; // Keep middle/selected value for compatibility
-                
-                rerValue.textContent = this.formatNumber(rer, 0) + ' cal/day';
-                
-                // Show MER as range if applicable
-                if (range.min !== range.max) {
-                    merValue.textContent = this.formatNumber(this.currentMERMin, 0) + '-' + 
-                                         this.formatNumber(this.currentMERMax, 0) + ' cal/day';
-                } else {
-                    merValue.textContent = this.formatNumber(mer, 0) + ' cal/day';
-                }
-                calorieResults.style.display = 'block';
-                
+                const kcalPerGram = kibbleEnergyPer100g / 100.0;
+                const dailyKcal = kibbleGrams * kcalPerGram;
+                this.currentMER = dailyKcal;
+                this.currentMERMin = dailyKcal;
+                this.currentMERMax = dailyKcal;
+
                 this.updateFoodCalculations();
             }
 
+            // Kaya: monthly table with interpolation between months
+            getKayaKibbleGramsForAge(ageMonths) {
+                // Precomputed monthly values for 30 kg (g/day)
+                const table = {
+                    2: 250,
+                    3: 330,
+                    4: 365,
+                    5: 382,
+                    6: 400,
+                    7: 405,
+                    8: 410,
+                    9: 410,
+                    10: 410,
+                    11: 408,
+                    12: 405
+                };
+                // Exact integer month
+                const lower = Math.floor(ageMonths);
+                const upper = Math.ceil(ageMonths);
+                if (lower === upper) return table[lower] || 0;
+                // Linear interpolation between bounds
+                const lowerVal = table[lower] || 0;
+                const upperVal = table[upper] || 0;
+                const t = (ageMonths - lower) / (upper - lower);
+                return lowerVal + (upperVal - lowerVal) * t;
+            }
+
             updateCupsButtonState() {
                 const cupsButton = document.getElementById('cupsButton');
                 if (!cupsButton) return;
diff --git a/src/css/main.css b/src/css/main.css
index 5758566..d392c96 100644
--- a/src/css/main.css
+++ b/src/css/main.css
@@ -190,6 +190,12 @@
             color: var(--text-label);
         }
 
+        /* Kaya end-weight readonly field: compact, non-editable */
+        #kayaEndWeight {
+            width: 120px;
+            display: inline-block;
+        }
+
         .dog-calculator-results {
             background: linear-gradient(135deg, rgba(241, 154, 95, 0.08) 0%, rgba(241, 154, 95, 0.04) 100%);
             border: 1px solid rgba(241, 154, 95, 0.2);
diff --git a/src/index.html b/src/index.html
index 53503c0..baa165e 100644
--- a/src/index.html
+++ b/src/index.html
@@ -1,50 +1,18 @@
     <div class="dog-calculator-container" id="dogCalculator">
         <div class="dog-calculator-section">
             <div class="dog-calculator-section-header">
-                <h2>Dog's Characteristics</h2>
-                <div class="dog-calculator-unit-switch">
-                    <span class="dog-calculator-unit-label active" id="metricLabel">Metric</span>
-                    <label class="dog-calculator-switch">
-                        <input type="checkbox" id="unitToggle">
-                        <span class="dog-calculator-slider"></span>
-                    </label>
-                    <span class="dog-calculator-unit-label" id="imperialLabel">Imperial</span>
-                </div>
-            </div>
-            
-            <div class="dog-calculator-form-group">
-                <label for="dogType">Dog Type / Activity Level:</label>
-                <select id="dogType" aria-describedby="dogTypeHelp">
-                    <option value="">Select dog type...</option>
-                    <option value="3.0">Puppy (0-4 months)</option>
-                    <option value="2.0">Puppy (4 months - adult)</option>
-                    <option value="1.2">Adult - inactive/obese</option>
-                    <option value="1.6">Adult (neutered/spayed) - average activity</option>
-                    <option value="1.8">Adult (intact) - average activity</option>
-                    <option value="1.0">Adult - weight loss</option>
-                    <option value="1.7">Adult - weight gain</option>
-                    <option value="2.0">Working dog - light work</option>
-                    <option value="3.0">Working dog - moderate work</option>
-                    <option value="5.0">Working dog - heavy work</option>
-                    <option value="1.1">Senior dog</option>
-                </select>
+                <h2>Kaya’s Transition</h2>
             </div>
 
             <div class="dog-calculator-form-group">
-                <label for="weight" id="weightLabel">Dog's Weight (kg):</label>
-                <input type="number" id="weight" min="0.1" step="0.1" placeholder="Enter weight in kg" aria-describedby="weightHelp">
-                <div id="weightError" class="dog-calculator-error dog-calculator-hidden">Please enter a valid weight (minimum 0.1 kg)</div>
+                <label for="ageMonths">Kaya’s age (months):</label>
+                <input type="number" id="ageMonths" min="2" max="12" step="0.1" placeholder="Enter age in months" aria-describedby="ageHelp">
+                <div id="ageClampNote" class="dog-calculator-error dog-calculator-hidden">Age adjusted to the supported 2–12 month range.</div>
             </div>
 
-            <div class="dog-calculator-results" id="calorieResults" style="display: none;">
-                <div class="dog-calculator-result-item">
-                    <span class="dog-calculator-result-label">Resting Energy Requirement (RER):</span>
-                    <span class="dog-calculator-result-value" id="rerValue">- cal/day</span>
-                </div>
-                <div class="dog-calculator-result-item">
-                    <span class="dog-calculator-result-label">Maintenance Energy Requirement (MER):</span>
-                    <span class="dog-calculator-result-value" id="merValue">- cal/day</span>
-                </div>
+            <div class="dog-calculator-form-group">
+                <label for="kayaEndWeight">Kaya’s end‑weight:</label>
+                <input type="text" id="kayaEndWeight" value="30 kg" readonly>
             </div>
         </div>
 
@@ -139,44 +107,10 @@
             </div>
         </div>
 
-        <div class="dog-calculator-action-buttons">
-            <button class="dog-calculator-btn dog-calculator-btn-share" id="shareBtn">
-                Share
-            </button>
-        </div>
-
         <div class="dog-calculator-footer">
             <a href="https://caninenutritionandwellness.com" target="_blank" rel="noopener noreferrer">
                 by caninenutritionandwellness.com
             </a>
         </div>
-        <!-- Share Modal -->
-        <div id="shareModal" class="dog-calculator-modal" style="display: none;">
-            <div class="dog-calculator-modal-content">
-                <span class="dog-calculator-modal-close" id="shareModalClose">&times;</span>
-                <h3>Share Calculator</h3>
-                <div class="dog-calculator-share-buttons">
-                    <button class="dog-calculator-share-btn dog-calculator-share-facebook plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-facebook" id="shareFacebook">
-                        Facebook
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-twitter plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-twitter" id="shareTwitter">
-                        Twitter
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-linkedin plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-linkedin" id="shareLinkedIn">
-                        LinkedIn
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-email plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-email" id="shareEmail">
-                        Email
-                    </button>
-                    <button class="dog-calculator-share-btn dog-calculator-share-copy plausible-event-name=Calculator+Usage plausible-event-action=calculator-share-copy-link" id="shareCopy">
-                        Copy Link
-                    </button>
-                </div>
-                <div class="dog-calculator-share-url">
-                    <input type="text" id="shareUrl" readonly>
-                </div>
-            </div>
-        </div>
 
-        
     </div>
diff --git a/src/js/calculator.js b/src/js/calculator.js
index 1dee12c..2753647 100644
--- a/src/js/calculator.js
+++ b/src/js/calculator.js
@@ -15,6 +15,9 @@
                 this.maxFoodSources = CALCULATOR_CONFIG.maxFoodSources;
                 this.mealsPerDay = 2;
                 this.showPerMeal = false;
+                // Kayafied reference source tracking
+                this.kibbleRefId = null;
+                this.gcRefId = null;
                 this.init();
             }
 
@@ -69,8 +72,45 @@
 
             // Food Source Management Methods
             initializeFoodSources() {
-                this.addFoodSource();
+                // Seed three sources for Kaya's transition
+                const gc = {
+                    id: this.generateFoodSourceId(),
+                    name: 'Fred & Felia, gently cooked',
+                    energy: '115',
+                    energyUnit: 'kcal100g',
+                    percentage: 5,
+                    isLocked: false
+                };
+                this.foodSources.push(gc);
+                this.renderFoodSource(gc);
+                this.gcRefId = gc.id;
+
+                const kibble = {
+                    id: this.generateFoodSourceId(),
+                    name: 'Eukanuba, kibble',
+                    energy: '372',
+                    energyUnit: 'kcal100g',
+                    percentage: 95,
+                    isLocked: false
+                };
+                this.foodSources.push(kibble);
+                this.renderFoodSource(kibble);
+                this.kibbleRefId = kibble.id;
+
+                const treats = {
+                    id: this.generateFoodSourceId(),
+                    name: 'Treats',
+                    energy: '',
+                    energyUnit: 'kcal100g',
+                    percentage: 0,
+                    isLocked: false
+                };
+                this.foodSources.push(treats);
+                this.renderFoodSource(treats);
+
                 this.updateAddButton();
+                this.updateRemoveButtons();
+                this.refreshAllPercentageUI();
             }
 
             addFoodSource() {
@@ -105,6 +145,9 @@
                 if (index === -1) return;
 
                 this.foodSources.splice(index, 1);
+                // If reference IDs were removed, clear them
+                if (this.kibbleRefId === id) this.kibbleRefId = null;
+                if (this.gcRefId === id) this.gcRefId = null;
                 
                 // Remove the DOM element
                 const element = document.getElementById(`foodSource-${id}`);
@@ -118,6 +161,7 @@
                 this.updateAddButton();
                 this.updateRemoveButtons();
                 this.refreshAllPercentageUI();
+                this.updateCalorieCalculations();
             }
 
             generateFoodSourceId() {
@@ -589,6 +633,10 @@
                 if (energyInput) {
                     energyInput.addEventListener('input', () => {
                         this.updateFoodSourceData(id, 'energy', energyInput.value);
+                        // If kibble reference changed, recompute daily target
+                        if (id === this.kibbleRefId) {
+                            this.updateCalorieCalculations();
+                        }
                         
                         // Auto-select cups when entering energy for kcal/cup
                         const foodSource = this.foodSources.find(fs => fs.id === id);
@@ -626,6 +674,9 @@
                 if (energyUnitSelect) {
                     energyUnitSelect.addEventListener('change', () => {
                         this.updateFoodSourceData(id, 'energyUnit', energyUnitSelect.value);
+                        if (id === this.kibbleRefId) {
+                            this.updateCalorieCalculations();
+                        }
                         
                         // Auto-select the most appropriate unit based on energy unit
                         const unitSelect = document.getElementById('unit');
@@ -803,6 +854,7 @@
             bindEvents() {
                 const weightInput = document.getElementById('weight');
                 const dogTypeSelect = document.getElementById('dogType');
+                const ageInput = document.getElementById('ageMonths');
                 const daysInput = document.getElementById('days');
                 const unitSelect = document.getElementById('unit');
                 const unitToggle = document.getElementById('unitToggle');
@@ -814,6 +866,12 @@
                 }
                 
                 if (dogTypeSelect) dogTypeSelect.addEventListener('change', () => this.updateCalorieCalculations());
+
+                // Kayafied: age input drives energy target
+                if (ageInput) {
+                    ageInput.addEventListener('input', () => this.updateCalorieCalculations());
+                    ageInput.addEventListener('blur', () => this.updateCalorieCalculations());
+                }
                 
                 if (daysInput) {
                     daysInput.addEventListener('input', () => {
@@ -1158,57 +1216,86 @@
             }
 
             updateCalorieCalculations() {
-                const dogTypeSelect = document.getElementById('dogType');
-                const calorieResults = document.getElementById('calorieResults');
-                const rerValue = document.getElementById('rerValue');
-                const merValue = document.getElementById('merValue');
+                // Kaya-specific: compute daily kcal target from age + kibble energy
+                const ageInput = document.getElementById('ageMonths');
+                const ageClampNote = document.getElementById('ageClampNote');
 
-                if (!dogTypeSelect || !calorieResults || !rerValue || !merValue) {
+                // Default: hide clamp note
+                if (ageClampNote) ageClampNote.classList.add('dog-calculator-hidden');
+
+                if (!ageInput || !ageInput.value) {
+                    this.currentMER = 0;
+                    this.currentMERMin = 0;
+                    this.currentMERMax = 0;
                     return;
                 }
 
-                const weightKg = this.getWeightInKg();
-                const dogTypeFactor = dogTypeSelect.value;
-                
-                this.showError('weightError', false);
-                
-                if (!weightKg || weightKg < 0.1) {
-                    const weightInput = document.getElementById('weight');
-                    if (weightInput && weightInput.value) this.showError('weightError', true);
-                    calorieResults.style.display = 'none';
+                let age = parseFloat(ageInput.value);
+                if (isNaN(age)) {
+                    this.currentMER = 0;
+                    this.currentMERMin = 0;
+                    this.currentMERMax = 0;
                     return;
                 }
 
-                if (!dogTypeFactor) {
-                    calorieResults.style.display = 'none';
+                // Clamp age to [2, 12]
+                if (age < 2) { age = 2; if (ageClampNote) ageClampNote.classList.remove('dog-calculator-hidden'); }
+                if (age > 12) { age = 12; if (ageClampNote) ageClampNote.classList.remove('dog-calculator-hidden'); }
+
+                // Calculate interpolated kibble grams/day for 30 kg at this age
+                const kibbleGrams = this.getKayaKibbleGramsForAge(age);
+
+                // Get kibble reference energy density in kcal/100g
+                let kibbleEnergyPer100g = null;
+                if (this.kibbleRefId) {
+                    const kibbleRef = this.foodSources.find(fs => fs.id === this.kibbleRefId);
+                    kibbleEnergyPer100g = kibbleRef ? this.getFoodSourceEnergyPer100g(kibbleRef) : null;
+                }
+
+                if (!kibbleEnergyPer100g || kibbleEnergyPer100g <= 0) {
+                    // Cannot compute without kibble energy density
+                    this.currentMER = 0;
+                    this.currentMERMin = 0;
+                    this.currentMERMax = 0;
                     return;
                 }
 
-                const factor = parseFloat(dogTypeFactor);
-                
-                const rer = this.calculateRER(weightKg);
-                const mer = this.calculateMER(rer, factor);
-                
-                // Calculate range for MER
-                const range = this.getLifeStageRange(factor);
-                this.currentMERMin = this.calculateMER(rer, range.min);
-                this.currentMERMax = this.calculateMER(rer, range.max);
-                this.currentMER = mer; // Keep middle/selected value for compatibility
-                
-                rerValue.textContent = this.formatNumber(rer, 0) + ' cal/day';
-                
-                // Show MER as range if applicable
-                if (range.min !== range.max) {
-                    merValue.textContent = this.formatNumber(this.currentMERMin, 0) + '-' + 
-                                         this.formatNumber(this.currentMERMax, 0) + ' cal/day';
-                } else {
-                    merValue.textContent = this.formatNumber(mer, 0) + ' cal/day';
-                }
-                calorieResults.style.display = 'block';
-                
+                const kcalPerGram = kibbleEnergyPer100g / 100.0;
+                const dailyKcal = kibbleGrams * kcalPerGram;
+                this.currentMER = dailyKcal;
+                this.currentMERMin = dailyKcal;
+                this.currentMERMax = dailyKcal;
+
                 this.updateFoodCalculations();
             }
 
+            // Kaya: monthly table with interpolation between months
+            getKayaKibbleGramsForAge(ageMonths) {
+                // Precomputed monthly values for 30 kg (g/day)
+                const table = {
+                    2: 250,
+                    3: 330,
+                    4: 365,
+                    5: 382,
+                    6: 400,
+                    7: 405,
+                    8: 410,
+                    9: 410,
+                    10: 410,
+                    11: 408,
+                    12: 405
+                };
+                // Exact integer month
+                const lower = Math.floor(ageMonths);
+                const upper = Math.ceil(ageMonths);
+                if (lower === upper) return table[lower] || 0;
+                // Linear interpolation between bounds
+                const lowerVal = table[lower] || 0;
+                const upperVal = table[upper] || 0;
+                const t = (ageMonths - lower) / (upper - lower);
+                return lowerVal + (upperVal - lowerVal) * t;
+            }
+
             updateCupsButtonState() {
                 const cupsButton = document.getElementById('cupsButton');
                 if (!cupsButton) return;