diff --git a/backend/engine.py b/backend/engine.py
new file mode 100644
index 0000000..819fb45
--- /dev/null
+++ b/backend/engine.py
@@ -0,0 +1,248 @@
+import math
+import time
+
+# Drug Catalog mirroring config.js
+DRUG_CONFIGS = {
+    'weed': {'rawCost': 10, 'sellPrice': 16, 'produceRate': 1.0, 'sellRate': 1.0, 'workerCost': 100, 'dealerCost': 150, 'unlockCost': 0},
+    'shrooms': {'rawCost': 35, 'sellPrice': 65, 'produceRate': 0.8, 'sellRate': 0.8, 'workerCost': 450, 'dealerCost': 650, 'unlockCost': 500},
+    'adderall': {'rawCost': 120, 'sellPrice': 240, 'produceRate': 0.6, 'sellRate': 0.6, 'workerCost': 2000, 'dealerCost': 3000, 'unlockCost': 2500},
+    'meth': {'rawCost': 400, 'sellPrice': 950, 'produceRate': 0.5, 'sellRate': 0.5, 'workerCost': 8000, 'dealerCost': 12000, 'unlockCost': 10000},
+    'mdma': {'rawCost': 1200, 'sellPrice': 3200, 'produceRate': 0.4, 'sellRate': 0.4, 'workerCost': 28000, 'dealerCost': 40000, 'unlockCost': 35000},
+    'ketamine': {'rawCost': 3800, 'sellPrice': 11000, 'produceRate': 0.35, 'sellRate': 0.35, 'workerCost': 95000, 'dealerCost': 140000, 'unlockCost': 120000},
+    'cocaine': {'rawCost': 12000, 'sellPrice': 38000, 'produceRate': 0.3, 'sellRate': 0.3, 'workerCost': 320000, 'dealerCost': 480000, 'unlockCost': 400000},
+    'crack': {'rawCost': 35000, 'sellPrice': 115000, 'produceRate': 0.25, 'sellRate': 0.25, 'workerCost': 900000, 'dealerCost': 1400000, 'unlockCost': 1200000},
+    'heroin': {'rawCost': 110000, 'sellPrice': 420000, 'produceRate': 0.2, 'sellRate': 0.2, 'workerCost': 3500000, 'dealerCost': 5500000, 'unlockCost': 4500000},
+    'fentanyl': {'rawCost': 450000, 'sellPrice': 2100000, 'produceRate': 0.15, 'sellRate': 0.15, 'workerCost': 15000000, 'dealerCost': 24000000, 'unlockCost': 20000000}
+}
+
+SYNTHESIS_RECIPES = {
+    'calvin_klein': {'ingredients': {'cocaine': 5, 'ketamine': 5}, 'payout': 95000},
+    'speedball': {'ingredients': {'heroin': 3, 'cocaine': 3}, 'payout': 850000},
+    'candy_flip': {'ingredients': {'shrooms': 15, 'mdma': 10}, 'payout': 75000}
+}
+
+SKILL_COSTS = {
+    'chem_1': 500, 'chem_2': 15000, 'chem_3': 250000,
+    'king_1': 1000, 'king_2': 35000, 'king_3': 600000,
+    'smug_1': 2000, 'smug_2': 50000, 'smug_3': 1000000
+}
+
+def clean_round(val: float) -> float:
+    """Rounds float gracefully to 1 decimal place without floating point anomalies."""
+    if math.isnan(val) or math.isinf(val) or val < 0:
+        return 0.0
+    return round(float(val), 1)
+
+def get_initial_state() -> dict:
+    state = {
+        'cash': 25.0,
+        'cleanBonds': 0,
+        'heat': 0.0,
+        'totalEarned': 0.0,
+        'lastTick': time.time(),
+        'drugs': {},
+        'skills': {s: False for s in SKILL_COSTS},
+        'achievements': {},
+        'synthesis': {r: 0 for r in SYNTHESIS_RECIPES}
+    }
+    for drug_id, cfg in DRUG_CONFIGS.items():
+        state['drugs'][drug_id] = {
+            'unlocked': (drug_id == 'weed'),
+            'raw': 0.0,
+            'product': 0.0,
+            'workers': 0,
+            'dealers': 0
+        }
+    return state
+
+def get_multipliers(state: dict):
+    bonds = state.get('cleanBonds', 0)
+    skills = state.get('skills', {})
+    achievements = state.get('achievements', {})
+
+    prod_m = 1.0 + (bonds * 0.03)
+    if skills.get('chem_1'): prod_m += 0.15
+    if achievements.get('millionaire'): prod_m += 0.20
+
+    sell_m = 1.0 + (bonds * 0.04)
+    if skills.get('king_2'): sell_m += 0.25
+    if achievements.get('first_hit'): sell_m += 0.05
+    if achievements.get('cartel_tier'): sell_m += 0.15
+
+    raw_m = 0.85 if skills.get('chem_2') else 1.0
+
+    dealer_m = 1.0
+    if skills.get('king_1'): dealer_m += 0.20
+    if skills.get('king_3'): dealer_m += 0.50
+
+    return prod_m, sell_m, raw_m, dealer_m
+
+def process_offline_and_ticks(state: dict) -> dict:
+    now = time.time()
+    last = state.get('lastTick', now)
+    delta = min(max(0.0, now - last), 86400.0) # Cap at 24h offline
+    state['lastTick'] = now
+
+    if delta <= 0:
+        return sanitize_state(state)
+
+    prod_m, sell_m, raw_m, dealer_m = get_multipliers(state)
+
+    for drug_id, data in state.get('drugs', {}).items():
+        cfg = DRUG_CONFIGS.get(drug_id)
+        if not cfg or not data.get('unlocked'):
+            continue
+
+        # Workers production
+        workers = data.get('workers', 0)
+        raw = data.get('raw', 0.0)
+        if workers > 0 and raw > 0:
+            potential_prod = workers * cfg['produceRate'] * prod_m * delta
+            actual_prod = min(raw, potential_prod)
+            data['raw'] = max(0.0, raw - actual_prod)
+            data['product'] = data.get('product', 0.0) + actual_prod
+
+        # Dealers selling
+        dealers = data.get('dealers', 0)
+        product = data.get('product', 0.0)
+        if dealers > 0 and product > 0:
+            potential_sell = dealers * cfg['sellRate'] * dealer_m * delta
+            actual_sell = min(product, potential_sell)
+            data['product'] = max(0.0, product - actual_sell)
+            rev = actual_sell * cfg['sellPrice'] * sell_m
+            state['cash'] = state.get('cash', 0.0) + rev
+            state['totalEarned'] = state.get('totalEarned', 0.0) + rev
+
+    # Heat decay
+    state['heat'] = max(0.0, state.get('heat', 0.0) - (0.5 * delta))
+
+    return sanitize_state(state)
+
+def apply_actions(state: dict, actions: list) -> dict:
+    """Applies and authorizes player actions sequentially against server authority."""
+    prod_m, sell_m, raw_m, dealer_m = get_multipliers(state)
+
+    for act in actions:
+        action_type = act.get('type')
+        drug_id = act.get('drug_id')
+
+        if action_type == 'buy_raw' and drug_id in DRUG_CONFIGS:
+            cfg = DRUG_CONFIGS[drug_id]
+            cost = cfg['rawCost'] * raw_m
+            amount = max(1, int(act.get('amount', 1)))
+            total_cost = cost * amount
+            if state['cash'] >= total_cost:
+                state['cash'] -= total_cost
+                state['drugs'][drug_id]['raw'] = state['drugs'][drug_id].get('raw', 0.0) + amount
+
+        elif action_type == 'manufacture' and drug_id in DRUG_CONFIGS:
+            data = state['drugs'][drug_id]
+            amount = max(1, int(act.get('amount', 1)))
+            actual = min(amount, int(data.get('raw', 0)))
+            if actual > 0:
+                data['raw'] -= actual
+                yield_count = actual
+                if state.get('skills', {}).get('chem_3'):
+                    # Purity proc bonus
+                    yield_count *= 1.3
+                data['product'] = data.get('product', 0.0) + yield_count
+                state['heat'] = min(100.0, state.get('heat', 0.0) + (0.5 * actual))
+
+        elif action_type == 'sell_manual' and drug_id in DRUG_CONFIGS:
+            data = state['drugs'][drug_id]
+            cfg = DRUG_CONFIGS[drug_id]
+            amount = max(1, int(act.get('amount', 1)))
+            actual = min(amount, int(data.get('product', 0)))
+            if actual > 0:
+                data['product'] -= actual
+                profit = actual * cfg['sellPrice'] * sell_m
+                state['cash'] += profit
+                state['totalEarned'] += profit
+                state['heat'] = min(100.0, state.get('heat', 0.0) + (0.8 * actual))
+
+        elif action_type == 'hire_worker' and drug_id in DRUG_CONFIGS:
+            cfg = DRUG_CONFIGS[drug_id]
+            count = state['drugs'][drug_id].get('workers', 0)
+            cost = math.floor(cfg['workerCost'] * math.pow(1.15, count))
+            if state['cash'] >= cost:
+                state['cash'] -= cost
+                state['drugs'][drug_id]['workers'] = count + 1
+
+        elif action_type == 'hire_dealer' and drug_id in DRUG_CONFIGS:
+            cfg = DRUG_CONFIGS[drug_id]
+            count = state['drugs'][drug_id].get('dealers', 0)
+            cost = math.floor(cfg['dealerCost'] * math.pow(1.15, count))
+            if state['cash'] >= cost:
+                state['cash'] -= cost
+                state['drugs'][drug_id]['dealers'] = count + 1
+
+        elif action_type == 'unlock_drug' and drug_id in DRUG_CONFIGS:
+            cfg = DRUG_CONFIGS[drug_id]
+            cost = cfg['unlockCost']
+            if state['cash'] >= cost and not state['drugs'][drug_id].get('unlocked'):
+                state['cash'] -= cost
+                state['drugs'][drug_id]['unlocked'] = True
+
+        elif action_type == 'blend_recipe':
+            recipe_id = act.get('recipe_id')
+            if recipe_id in SYNTHESIS_RECIPES:
+                r = SYNTHESIS_RECIPES[recipe_id]
+                can_blend = True
+                for ingr_id, needed in r['ingredients'].items():
+                    if state['drugs'].get(ingr_id, {}).get('product', 0) < needed:
+                        can_blend = False
+                        break
+                if can_blend:
+                    for ingr_id, needed in r['ingredients'].items():
+                        state['drugs'][ingr_id]['product'] -= needed
+                    state['cash'] += r['payout']
+                    state['totalEarned'] += r['payout']
+                    state['heat'] = min(100.0, state.get('heat', 0.0) + 5.0)
+
+        elif action_type == 'buy_skill':
+            skill_id = act.get('skill_id')
+            if skill_id in SKILL_COSTS and not state.get('skills', {}).get(skill_id):
+                cost = SKILL_COSTS[skill_id]
+                if state['cash'] >= cost:
+                    state['cash'] -= cost
+                    state.setdefault('skills', {})[skill_id] = True
+
+        elif action_type == 'bribe_police':
+            bribe_cost = max(100.0, state['cash'] * 0.15)
+            if state['cash'] >= bribe_cost:
+                state['cash'] -= bribe_cost
+                state['heat'] = 0.0
+
+        elif action_type == 'flush_stash':
+            state['heat'] = 20.0
+
+        elif action_type == 'launder_prestige':
+            bonds_to_earn = math.floor(math.sqrt(max(0.0, state.get('totalEarned', 0.0)) / 25000.0))
+            gain = max(0, bonds_to_earn - state.get('cleanBonds', 0))
+            if gain >= 1:
+                state['cleanBonds'] += gain
+                state['cash'] = 50.0
+                state['heat'] = 0.0
+                for d_id, d_data in state['drugs'].items():
+                    d_data['unlocked'] = (d_id == 'weed')
+                    d_data['raw'] = 0.0
+                    d_data['product'] = 0.0
+                    d_data['workers'] = 0
+                    d_data['dealers'] = 0
+
+    return sanitize_state(state)
+
+def sanitize_state(state: dict) -> dict:
+    """Enforces max 1 decimal and prevents negative or runaway numbers."""
+    state['cash'] = clean_round(state.get('cash', 0.0))
+    state['heat'] = clean_round(min(100.0, max(0.0, state.get('heat', 0.0))))
+    state['totalEarned'] = clean_round(state.get('totalEarned', 0.0))
+    state['cleanBonds'] = int(state.get('cleanBonds', 0))
+
+    for d_id, data in state.get('drugs', {}).items():
+        data['raw'] = clean_round(data.get('raw', 0.0))
+        data['product'] = clean_round(data.get('product', 0.0))
+        data['workers'] = int(data.get('workers', 0))
+        data['dealers'] = int(data.get('dealers', 0))
+
+    return state
diff --git a/backend/main.py b/backend/main.py
index 62a4e07..c1acc03 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -3,12 +3,12 @@ import sqlite3
 from fastapi import FastAPI, HTTPException, status, Depends
 from fastapi.middleware.cors import CORSMiddleware
 from database import init_db, get_db
-from models import RegisterRequest, LoginRequest, AuthResponse, SaveGameRequest
+from models import RegisterRequest, LoginRequest, AuthResponse, SaveGameRequest, SyncTickRequest
 from auth import hash_password, verify_password, create_access_token, get_current_user_id
+import engine
 
-app = FastAPI(title="El Puro API", version="1.0.0")
+app = FastAPI(title="El Puro API", version="1.1.0")
 
-# Enable CORS for local and proxy flexibility
 app.add_middleware(
     CORSMiddleware,
     allow_origins=["*"],
@@ -23,13 +23,11 @@ def startup_event():
 
 @app.get("/api/health")
 def health_check():
-    return {"status": "ok", "app": "El Puro", "version": "1.0.0"}
+    return {"status": "ok", "app": "El Puro", "version": "1.1.0"}
 
 @app.post("/api/auth/register", response_model=AuthResponse)
 def register(req: RegisterRequest):
-    # HONEYPOT TRAP: If website_hp is populated, a bot filled it!
     if req.website_hp and req.website_hp.strip():
-        # Reject silently with generic bad request
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail="Registration verification failed."
@@ -49,6 +47,13 @@ def register(req: RegisterRequest):
                 (clean_username, hashed)
             )
             user_id = cursor.lastrowid
+            
+            # Initialize clean server authoritative game state
+            init_state = engine.get_initial_state()
+            cursor.execute(
+                "INSERT INTO saves (user_id, save_data, updated_at) VALUES (?, ?, CURRENT_TIMESTAMP)",
+                (user_id, json.dumps(init_state))
+            )
             conn.commit()
     except sqlite3.IntegrityError:
         raise HTTPException(
@@ -88,17 +93,57 @@ def get_game_state(user_id: int = Depends(get_current_user_id)):
         row = cursor.fetchone()
 
     if not row:
-        return {"has_save": False, "save_data": None}
+        init_state = engine.get_initial_state()
+        return {"has_save": True, "save_data": init_state, "updated_at": None}
 
     try:
         data = json.loads(row["save_data"])
+        # Process authoritative offline progress up to now
+        data = engine.process_offline_and_ticks(data)
         return {"has_save": True, "save_data": data, "updated_at": row["updated_at"]}
     except Exception:
-        return {"has_save": False, "save_data": None}
+        return {"has_save": True, "save_data": engine.get_initial_state(), "updated_at": None}
+
+@app.post("/api/game/tick")
+def sync_tick(req: SyncTickRequest, user_id: int = Depends(get_current_user_id)):
+    """Authoritative periodic tick (called every 5-10s): applies queued actions and computes tick progress."""
+    with get_db() as conn:
+        cursor = conn.cursor()
+        cursor.execute("SELECT save_data FROM saves WHERE user_id = ?", (user_id,))
+        row = cursor.fetchone()
+
+        if row:
+            try:
+                state = json.loads(row["save_data"])
+            except Exception:
+                state = engine.get_initial_state()
+        else:
+            state = engine.get_initial_state()
+
+        # 1. Apply authorized player actions
+        if req.actions:
+            state = engine.apply_actions(state, req.actions)
+
+        # 2. Advance production, automation, and offline ticks
+        state = engine.process_offline_and_ticks(state)
+
+        # 3. Persist authoritative clean state
+        cursor.execute("""
+            INSERT INTO saves (user_id, save_data, updated_at)
+            VALUES (?, ?, CURRENT_TIMESTAMP)
+            ON CONFLICT(user_id) DO UPDATE SET
+                save_data = excluded.save_data,
+                updated_at = CURRENT_TIMESTAMP
+        """, (user_id, json.dumps(state)))
+        conn.commit()
+
+    return {"status": "ok", "save_data": state}
 
 @app.post("/api/game/save")
 def save_game_state(req: SaveGameRequest, user_id: int = Depends(get_current_user_id)):
-    json_data = json.dumps(req.save_data)
+    # Sanitize data before persisting
+    clean_state = engine.sanitize_state(req.save_data)
+    json_data = json.dumps(clean_state)
     with get_db() as conn:
         cursor = conn.cursor()
         cursor.execute("""
@@ -110,4 +155,4 @@ def save_game_state(req: SaveGameRequest, user_id: int = Depends(get_current_use
         """, (user_id, json_data))
         conn.commit()
 
-    return {"status": "saved"}
+    return {"status": "saved", "save_data": clean_state}
diff --git a/backend/models.py b/backend/models.py
index 105c45b..0900ec3 100644
--- a/backend/models.py
+++ b/backend/models.py
@@ -1,5 +1,5 @@
 from pydantic import BaseModel, Field
-from typing import Optional, Dict, Any
+from typing import Optional, Dict, Any, List
 
 class RegisterRequest(BaseModel):
     username: str = Field(..., min_length=3, max_length=32)
@@ -15,5 +15,8 @@ class AuthResponse(BaseModel):
     token: str
     username: str
 
+class SyncTickRequest(BaseModel):
+    actions: List[Dict[str, Any]] = []
+
 class SaveGameRequest(BaseModel):
     save_data: Dict[str, Any]
diff --git a/frontend/js/api.js b/frontend/js/api.js
index 3f1a342..5995c42 100644
--- a/frontend/js/api.js
+++ b/frontend/js/api.js
@@ -75,6 +75,31 @@ const API = {
         }
     },
 
+    async syncTick(actions = []) {
+        const token = this.getToken();
+        if (!token) return null;
+
+        try {
+            const res = await fetch('/api/game/tick', {
+                method: 'POST',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'Authorization': `Bearer ${token}`
+                },
+                body: JSON.stringify({ actions })
+            });
+            if (!res.ok) {
+                if (res.status === 401) this.logout();
+                return null;
+            }
+            const data = await res.json();
+            return data.save_data;
+        } catch (e) {
+            console.warn('Network tick failed, queuing actions', e);
+            return null;
+        }
+    },
+
     async saveRemote(saveData) {
         const token = this.getToken();
         if (!token) return;
diff --git a/frontend/js/game.js b/frontend/js/game.js
index ee73186..2463668 100644
--- a/frontend/js/game.js
+++ b/frontend/js/game.js
@@ -1,10 +1,10 @@
-// EL PURO - SilkNet OS Core Engine
+// EL PURO - SilkNet OS Core Engine (Authoritative Server Synchronization)
 
 const INITIAL_GAME_STATE = {
-    cash: 25.00,
+    cash: 25.0,
     cleanBonds: 0,
-    heat: 0,
-    totalEarned: 0,
+    heat: 0.0,
+    totalEarned: 0.0,
     activeTab: 'lab',
     drugs: {},
     skills: {},
@@ -17,8 +17,8 @@ const INITIAL_GAME_STATE = {
 DRUG_CATALOG.forEach(d => {
     INITIAL_GAME_STATE.drugs[d.id] = {
         unlocked: d.unlockedDefault,
-        raw: 0,
-        product: 0,
+        raw: 0.0,
+        product: 0.0,
         workers: 0,
         dealers: 0
     };
@@ -37,9 +37,22 @@ SYNTHESIS_RECIPES.forEach(r => {
 });
 
 let G = JSON.parse(JSON.stringify(INITIAL_GAME_STATE));
-let cashRateTracker = 0;
-let lastSaveTime = Date.now();
-let lastRaidCheck = Date.now();
+let cashRateTracker = 0.0;
+let pendingActions = []; // Actions queued between 6-second authoritative server ticks
+let isSyncing = false;
+
+// --- NUMBER FORMATTING HELPER (Max 1 decimal, graceful fallback) ---
+function fmtNum(val) {
+    if (val === undefined || val === null || isNaN(val) || !isFinite(val)) return '0';
+    const rounded = Math.round(Number(val) * 10) / 10;
+    // If it's an integer, show with .0 for uniform currency or clean integer for items
+    return rounded.toLocaleString(undefined, { minimumFractionDigits: 1, maximumFractionDigits: 1 });
+}
+
+function fmtInt(val) {
+    if (val === undefined || val === null || isNaN(val) || !isFinite(val)) return '0';
+    return Math.floor(Math.max(0, Number(val))).toLocaleString();
+}
 
 // --- DOM CACHE ---
 const dom = {
@@ -61,7 +74,6 @@ const dom = {
 // --- MULTIPLIERS & BONUSES ---
 function getProductionMultiplier() {
     let m = 1.0;
-    // Clean bonds: +3% production each
     m += G.cleanBonds * 0.03;
     if (G.skills['chem_1']) m += 0.15;
     if (G.achievements['millionaire']) m += 0.20;
@@ -70,7 +82,6 @@ function getProductionMultiplier() {
 
 function getSellPriceMultiplier() {
     let m = 1.0;
-    // Clean bonds: +4% sell price each
     m += G.cleanBonds * 0.04;
     if (G.skills['king_2']) m += 0.25;
     if (G.achievements['first_hit']) m += 0.05;
@@ -152,7 +163,7 @@ function renderLabView() {
     `;
 
     DRUG_CATALOG.forEach(d => {
-        const data = G.drugs[d.id];
+        const data = G.drugs[d.id] || { raw: 0, product: 0, workers: 0, dealers: 0, unlocked: false };
         const rawCost = Math.floor(d.rawCost * getRawCostMultiplier());
         const workerCost = getWorkerCost(d.id);
 
@@ -199,11 +210,11 @@ function renderLabView() {
                 <div class="card-stats-row">
                     <div class="stat-item">
                         <span class="stat-label">${d.rawName}</span>
-                        <span class="stat-value" id="val-raw-${d.id}">${data.raw}</span>
+                        <span class="stat-value" id="val-raw-${d.id}">${fmtNum(data.raw)}</span>
                     </div>
                     <div class="stat-item">
                         <span class="stat-label">${d.productName}</span>
-                        <span class="stat-value" id="val-prod-${d.id}">${data.product}g</span>
+                        <span class="stat-value" id="val-prod-${d.id}">${fmtNum(data.product)}g</span>
                     </div>
                 </div>
 
@@ -246,7 +257,7 @@ function renderStreetsView() {
         </div>
     `;
 
-    DRUG_CATALOG.filter(d => G.drugs[d.id].unlocked).forEach(d => {
+    DRUG_CATALOG.filter(d => G.drugs[d.id] && G.drugs[d.id].unlocked).forEach(d => {
         const data = G.drugs[d.id];
         const dealerCost = getDealerCost(d.id);
         const unitPrice = Math.floor(d.sellPrice * getSellPriceMultiplier());
@@ -271,11 +282,11 @@ function renderStreetsView() {
                 <div class="card-stats-row">
                     <div class="stat-item">
                         <span class="stat-label">In Stash</span>
-                        <span class="stat-value">${data.product}g</span>
+                        <span class="stat-value" id="val-prod-street-${d.id}">${fmtNum(data.product)}g</span>
                     </div>
                     <div class="stat-item">
                         <span class="stat-label">Deal Speed</span>
-                        <span class="stat-value">${(data.dealers * d.sellRate * getDealerSpeedMultiplier()).toFixed(1)}/s</span>
+                        <span class="stat-value">${fmtNum(data.dealers * d.sellRate * getDealerSpeedMultiplier())}/s</span>
                     </div>
                 </div>
 
@@ -286,7 +297,7 @@ function renderStreetsView() {
                     </button>
                     <button class="btn-tactical" onclick="sellManual('${d.id}', 10)" ${data.product < 10 ? 'disabled' : ''}>
                         Sell 10x Stash
-                        <span class="btn-subtext">+$${(unitPrice * Math.min(10, data.product)).toLocaleString()}</span>
+                        <span class="btn-subtext">+$${(unitPrice * Math.min(10, Math.floor(data.product))).toLocaleString()}</span>
                     </button>
                 </div>
             </div>
@@ -309,7 +320,7 @@ function renderStreetsView() {
         const ingrLabels = Object.entries(r.ingredients).map(([id, amt]) => {
             const has = G.drugs[id] ? G.drugs[id].product : 0;
             const drugDef = DRUG_CATALOG.find(d => d.id === id);
-            return `<span style="color: ${has >= amt ? '#22c55e' : '#ef4444'}">${amt}g ${drugDef.name} (${has}g)</span>`;
+            return `<span style="color: ${has >= amt ? '#22c55e' : '#ef4444'}">${amt}g ${drugDef.name} (${fmtNum(has)}g)</span>`;
         }).join(' + ');
 
         html += `
@@ -412,7 +423,7 @@ function renderOffshoreView() {
             <div style="background: #090e13; border: 1px solid #1f2a36; border-radius: 8px; padding: 12px; margin-bottom: 14px; font-family: var(--font-mono);">
                 <div style="font-size: 0.7rem; color: var(--text-secondary);">CLEAN BONDS UPON LAUNDERING:</div>
                 <div style="font-size: 1.8rem; font-weight: 800; color: var(--neon-cyan);">+${nextBonds} Bonds</div>
-                <div style="font-size: 0.68rem; color: var(--text-muted);">Career Volume: $${Math.floor(G.totalEarned).toLocaleString()}</div>
+                <div style="font-size: 0.68rem; color: var(--text-muted);">Career Volume: $${fmtNum(G.totalEarned)}</div>
             </div>
             <button class="btn-tactical btn-sell-action" style="padding: 12px; font-size: 0.9rem;" onclick="launderMoney()" ${nextBonds < 1 ? 'disabled' : ''}>
                 ${nextBonds >= 1 ? 'Launder Cash & Reset Syndicate' : 'Need More Volume to Launder'}
@@ -444,15 +455,20 @@ function renderOffshoreView() {
     dom.viewport.innerHTML = html;
 }
 
-// --- CORE ACTIONS ---
+// --- OPTIMISTIC CLIENT ACTIONS (Queued for Server Authority) ---
+function queueAction(action) {
+    pendingActions.push(action);
+}
+
 function buyRaw(drugId) {
     const d = DRUG_CATALOG.find(x => x.id === drugId);
     const cost = Math.floor(d.rawCost * getRawCostMultiplier());
     if (G.cash >= cost) {
+        // Optimistic local UI update
         G.cash -= cost;
         G.drugs[drugId].raw += 1;
-        updateHud();
-        renderViewport();
+        queueAction({ type: 'buy_raw', drug_id: drugId, amount: 1 });
+        updateLiveInventory();
     }
 }
 
@@ -461,31 +477,30 @@ function manufacture(drugId) {
     if (data.raw >= 1) {
         data.raw -= 1;
         let yieldCount = 1;
-        // 99.1% crystallization perk
         if (G.skills['chem_3'] && Math.random() < 0.10) {
             yieldCount = 3;
             showToast('99.1% Purity Proc! 3x Yield!', false);
         }
         data.product += yieldCount;
         addHeat(0.5);
-        updateHud();
-        renderViewport();
+        queueAction({ type: 'manufacture', drug_id: drugId, amount: 1 });
+        updateLiveInventory();
     }
 }
 
 function sellManual(drugId, amount = 1) {
     const d = DRUG_CATALOG.find(x => x.id === drugId);
     const data = G.drugs[drugId];
-    const actual = Math.min(amount, data.product);
+    const actual = Math.min(amount, Math.floor(data.product));
     if (actual > 0) {
         data.product -= actual;
         const profit = actual * Math.floor(d.sellPrice * getSellPriceMultiplier());
         G.cash += profit;
         G.totalEarned += profit;
         addHeat(actual * 0.8);
+        queueAction({ type: 'sell_manual', drug_id: drugId, amount: actual });
         checkAchievements();
-        updateHud();
-        renderViewport();
+        updateLiveInventory();
     }
 }
 
@@ -494,9 +509,10 @@ function hireWorker(drugId) {
     if (G.cash >= cost) {
         G.cash -= cost;
         G.drugs[drugId].workers += 1;
+        queueAction({ type: 'hire_worker', drug_id: drugId });
         checkAchievements();
-        updateHud();
         renderViewport();
+        updateLiveInventory();
     }
 }
 
@@ -505,8 +521,9 @@ function hireDealer(drugId) {
     if (G.cash >= cost) {
         G.cash -= cost;
         G.drugs[drugId].dealers += 1;
-        updateHud();
+        queueAction({ type: 'hire_dealer', drug_id: drugId });
         renderViewport();
+        updateLiveInventory();
     }
 }
 
@@ -516,9 +533,10 @@ function unlockDrug(drugId) {
         G.cash -= cost;
         G.drugs[drugId].unlocked = true;
         showToast(`Unlocked formula for ${DRUG_CATALOG.find(d => d.id === drugId).name}!`);
+        queueAction({ type: 'unlock_drug', drug_id: drugId });
         checkAchievements();
-        updateHud();
         renderViewport();
+        updateLiveInventory();
     }
 }
 
@@ -532,9 +550,10 @@ function blendRecipe(recipeId) {
         G.cash += r.sellPrice;
         G.totalEarned += r.sellPrice;
         addHeat(5);
+        queueAction({ type: 'blend_recipe', recipe_id: recipeId });
         showToast(`Synthesized & Sold ${r.name} for +$${r.sellPrice.toLocaleString()}!`);
-        updateHud();
         renderViewport();
+        updateLiveInventory();
     }
 }
 
@@ -543,9 +562,10 @@ function buySkill(skillId) {
     if (G.cash >= s.cost && !G.skills[skillId]) {
         G.cash -= s.cost;
         G.skills[skillId] = true;
+        queueAction({ type: 'buy_skill', skill_id: skillId });
         showToast(`Skill Activated: ${s.name}`);
-        updateHud();
         renderViewport();
+        updateLiveInventory();
     }
 }
 
@@ -555,29 +575,30 @@ function launderMoney() {
     if (gain < 1) return;
 
     if (confirm(`Launder all assets for +${gain} Clean Offshore Bonds? Your syndicate operations will reset.`)) {
+        queueAction({ type: 'launder_prestige' });
         G.cleanBonds += gain;
-        G.cash = 50.00;
-        G.heat = 0;
+        G.cash = 50.0;
+        G.heat = 0.0;
         DRUG_CATALOG.forEach(d => {
             G.drugs[d.id] = {
                 unlocked: d.unlockedDefault,
-                raw: 0,
-                product: 0,
+                raw: 0.0,
+                product: 0.0,
                 workers: 0,
                 dealers: 0
             };
         });
         checkAchievements();
         showToast(`Laundered! You now have ${G.cleanBonds} Clean Bonds.`);
-        updateHud();
         renderViewport();
+        updateLiveInventory();
     }
 }
 
 // --- POLICE HEAT & RAIDS ---
 function addHeat(amount) {
     let riseMod = G.skills['smug_1'] ? 0.65 : 1.0;
-    G.heat = Math.min(100, G.heat + (amount * riseMod));
+    G.heat = Math.min(100.0, G.heat + (amount * riseMod));
 }
 
 function checkRaidEvent() {
@@ -594,20 +615,22 @@ function triggerRaidModal() {
     document.getElementById('btn-raid-bribe').onclick = () => {
         if (G.cash >= bribeCost) {
             G.cash -= bribeCost;
-            G.heat = 0;
+            G.heat = 0.0;
+            queueAction({ type: 'bribe_police' });
             dom.raidModal.classList.remove('active');
             showToast('Sheriff bribed. Heat cleared.');
-            updateHud();
+            updateLiveInventory();
         } else {
             showToast('Insufficient cash for bribe!', true);
         }
     };
 
     document.getElementById('btn-raid-stash').onclick = () => {
-        G.heat = 20;
+        G.heat = 20.0;
+        queueAction({ type: 'flush_stash' });
         dom.raidModal.classList.remove('active');
         showToast('Stash flushed & secured. Heat diminished.');
-        updateHud();
+        updateLiveInventory();
     };
 
     document.getElementById('btn-raid-shootout').onclick = () => {
@@ -615,18 +638,16 @@ function triggerRaidModal() {
         if (Math.random() < 0.5) {
             const reward = Math.floor(G.cash * 0.5);
             G.cash += reward;
-            G.heat = 0;
+            G.heat = 0.0;
             showToast(`Broke through blockade! Seized +$${reward.toLocaleString()}!`);
         } else {
-            // Seize 30% of inventory
             DRUG_CATALOG.forEach(d => {
                 G.drugs[d.id].product = Math.floor(G.drugs[d.id].product * 0.7);
             });
-            G.heat = 30;
+            G.heat = 30.0;
             showToast('Agents seized 30% of stored product!', true);
         }
-        updateHud();
-        renderViewport();
+        updateLiveInventory();
     };
 }
 
@@ -636,15 +657,15 @@ function checkAchievements() {
         G.achievements['first_hit'] = true;
         showToast('Achievement: First Batch!');
     }
-    if (G.drugs['weed'].workers >= 10 && !G.achievements['grower_op']) {
+    if (G.drugs['weed'] && G.drugs['weed'].workers >= 10 && !G.achievements['grower_op']) {
         G.achievements['grower_op'] = true;
         showToast('Achievement: Green Thumb!');
     }
-    if (G.drugs['meth'].unlocked && !G.achievements['blue_sky']) {
+    if (G.drugs['meth'] && G.drugs['meth'].unlocked && !G.achievements['blue_sky']) {
         G.achievements['blue_sky'] = true;
         showToast('Achievement: Say My Name!');
     }
-    if (G.drugs['cocaine'].unlocked && !G.achievements['cartel_tier']) {
+    if (G.drugs['cocaine'] && G.drugs['cocaine'].unlocked && !G.achievements['cartel_tier']) {
         G.achievements['cartel_tier'] = true;
         showToast('Achievement: El Patrón!');
     }
@@ -658,8 +679,8 @@ function checkAchievements() {
     }
 }
 
-// --- TICK & GAME LOOP ---
-function tick(deltaSec) {
+// --- LIGHTWEIGHT LOCAL TICK (Smooth 60FPS UI feedback between server syncs) ---
+function clientTick(deltaSec) {
     let earnedThisTick = 0;
     const prodMulti = getProductionMultiplier();
     const sellMulti = getSellPriceMultiplier();
@@ -667,21 +688,21 @@ function tick(deltaSec) {
 
     DRUG_CATALOG.forEach(d => {
         const data = G.drugs[d.id];
-        if (!data.unlocked) return;
+        if (!data || !data.unlocked) return;
 
         // Auto Production
         if (data.workers > 0 && data.raw > 0) {
             const prodPerSec = data.workers * d.produceRate * prodMulti;
             const toMake = Math.min(data.raw, prodPerSec * deltaSec);
-            data.raw -= toMake;
-            data.product += toMake;
+            data.raw = Math.max(0, data.raw - toMake);
+            data.product = data.product + toMake;
         }
 
         // Auto Sales
         if (data.dealers > 0 && data.product > 0) {
             const sellPerSec = data.dealers * d.sellRate * dealerSpeed;
             const toSell = Math.min(data.product, sellPerSec * deltaSec);
-            data.product -= toSell;
+            data.product = Math.max(0, data.product - toSell);
             const revenue = toSell * Math.floor(d.sellPrice * sellMulti);
             G.cash += revenue;
             G.totalEarned += revenue;
@@ -689,31 +710,70 @@ function tick(deltaSec) {
         }
     });
 
-    // Heat decay
     if (G.heat > 0) {
-        G.heat = Math.max(0, G.heat - (0.5 * deltaSec));
+        G.heat = Math.max(0.0, G.heat - (0.5 * deltaSec));
     }
 
     if (deltaSec > 0) {
         cashRateTracker = cashRateTracker * 0.85 + (earnedThisTick / deltaSec) * 0.15;
     }
 
-    // Periodic raid check
-    if (Date.now() - lastRaidCheck > 12000) {
-        lastRaidCheck = Date.now();
-        checkRaidEvent();
-    }
-
-    updateHud();
+    // Direct, surgical DOM text updates every tick (no lag, no re-rendering entire card HTML)
+    updateLiveInventory();
 }
 
-function updateHud() {
-    dom.cash.textContent = G.cash.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
-    dom.rate.textContent = cashRateTracker.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
-    dom.bonds.textContent = G.cleanBonds;
-    dom.multiplier.textContent = Math.round((G.cleanBonds * 4));
+function updateLiveInventory() {
+    dom.cash.textContent = fmtNum(G.cash);
+    dom.rate.textContent = fmtNum(cashRateTracker);
+    dom.bonds.textContent = fmtInt(G.cleanBonds);
+    dom.multiplier.textContent = fmtInt(G.cleanBonds * 4);
     dom.heatPct.textContent = `${Math.round(G.heat)}%`;
     dom.heatBar.style.width = `${Math.min(100, Math.round(G.heat))}%`;
+
+    // Surgically update raw and product text fields if they exist in DOM
+    DRUG_CATALOG.forEach(d => {
+        const rawEl = document.getElementById(`val-raw-${d.id}`);
+        if (rawEl && G.drugs[d.id]) {
+            rawEl.textContent = fmtNum(G.drugs[d.id].raw);
+        }
+        const prodEl = document.getElementById(`val-prod-${d.id}`);
+        if (prodEl && G.drugs[d.id]) {
+            prodEl.textContent = `${fmtNum(G.drugs[d.id].product)}g`;
+        }
+        const streetProdEl = document.getElementById(`val-prod-street-${d.id}`);
+        if (streetProdEl && G.drugs[d.id]) {
+            streetProdEl.textContent = `${fmtNum(G.drugs[d.id].product)}g`;
+        }
+    });
+}
+
+// --- AUTHORITATIVE SERVER TICK (Every 6 seconds) ---
+async function authoritativeServerTick() {
+    if (isSyncing) return;
+    isSyncing = true;
+
+    // Grab queued actions and reset local queue
+    const actionsToSend = [...pendingActions];
+    pendingActions = [];
+
+    if (API.getToken()) {
+        const serverState = await API.syncTick(actionsToSend);
+        if (serverState) {
+            // Reconcile authoritative server state (protects against browser devtools tampering)
+            G = {
+                ...INITIAL_GAME_STATE,
+                ...serverState,
+                activeTab: G.activeTab // Preserve UI view tab
+            };
+            checkAchievements();
+            updateLiveInventory();
+        }
+    } else {
+        // Guest mode / offline fallback: persist locally
+        localStorage.setItem('el_puro_local_save', JSON.stringify(G));
+    }
+
+    isSyncing = false;
 }
 
 // Game loop with requestAnimationFrame
@@ -722,39 +782,36 @@ function gameLoop(now) {
     const delta = (now - lastFrameTime) / 1000;
     lastFrameTime = now;
     if (delta > 0 && delta < 5) {
-        tick(delta);
+        clientTick(delta);
     }
     requestAnimationFrame(gameLoop);
 }
 
+// Server tick: exactly every 6 seconds to prevent flooding server
+setInterval(authoritativeServerTick, 6000);
+
 // Clock updates
 setInterval(() => {
     const d = new Date();
     dom.clock.textContent = d.toTimeString().substring(0, 5);
 }, 1000);
 
-// Auto-save every 5 seconds (Local & Cloud)
-setInterval(async () => {
-    localStorage.setItem('el_puro_local_save', JSON.stringify(G));
-    if (API.getToken()) {
-        await API.saveRemote(G);
-    }
-}, 5000);
+// Periodic raid check (every 15 seconds)
+setInterval(checkRaidEvent, 15000);
 
 // --- INITIALIZATION & EVENTS ---
 document.addEventListener('DOMContentLoaded', async () => {
-    // Check auth status
     const username = API.getUsername();
     if (username) {
         dom.userBadge.textContent = `[${username}]`;
     }
 
-    // Load Save: Try cloud first if logged in, fallback to local
+    // Load initial authoritative save from server if logged in
     let loaded = false;
     if (API.getToken()) {
         const remote = await API.loadRemoteSave();
         if (remote) {
-            G = { ...INITIAL_GAME_STATE, ...remote };
+            G = { ...INITIAL_GAME_STATE, ...remote, activeTab: 'lab' };
             loaded = true;
         }
     }
@@ -762,9 +819,9 @@ document.addEventListener('DOMContentLoaded', async () => {
         const local = localStorage.getItem('el_puro_local_save');
         if (local) {
             try {
-                G = { ...INITIAL_GAME_STATE, ...JSON.parse(local) };
+                G = { ...INITIAL_GAME_STATE, ...JSON.parse(local), activeTab: 'lab' };
             } catch (e) {
-                console.warn('Corrupt local save, initializing new game');
+                console.warn('Corrupt local save, using initial state');
             }
         }
     }
@@ -788,10 +845,10 @@ document.addEventListener('DOMContentLoaded', async () => {
             dom.userBadge.textContent = `[${res.username}]`;
             dom.authModal.classList.remove('active');
             showToast(`Connected: Welcome ${res.username}`);
-            // Sync game save from cloud
+            // Fetch server authoritative state
             const remote = await API.loadRemoteSave();
             if (remote) {
-                G = { ...INITIAL_GAME_STATE, ...remote };
+                G = { ...INITIAL_GAME_STATE, ...remote, activeTab: G.activeTab };
                 renderViewport();
             }
         } catch (e) {
@@ -802,7 +859,7 @@ document.addEventListener('DOMContentLoaded', async () => {
     document.getElementById('btn-register-submit').addEventListener('click', async () => {
         const u = document.getElementById('auth-username').value.trim();
         const p = document.getElementById('auth-password').value;
-        const hp = document.getElementById('auth-website-hp').value; // Honeypot field!
+        const hp = document.getElementById('auth-website-hp').value;
         if (!u || !p) return showToast('Enter username and password', true);
 
         try {
@@ -810,13 +867,18 @@ document.addEventListener('DOMContentLoaded', async () => {
             dom.userBadge.textContent = `[${res.username}]`;
             dom.authModal.classList.remove('active');
             showToast(`Syndicate registered: ${res.username}`);
-            await API.saveRemote(G);
+            // Fetch clean server initialized state
+            const remote = await API.loadRemoteSave();
+            if (remote) {
+                G = { ...INITIAL_GAME_STATE, ...remote, activeTab: G.activeTab };
+                renderViewport();
+            }
         } catch (e) {
             showToast(e.message, true);
         }
     });
 
     renderViewport();
-    updateHud();
+    updateLiveInventory();
     requestAnimationFrame(gameLoop);
 });