diff --git a/scripts/deploy.sh b/scripts/deploy.sh
index 46ee79f..b7b2d61 100755
--- a/scripts/deploy.sh
+++ b/scripts/deploy.sh
@@ -51,7 +51,7 @@ info() {
 }
 
 # Check root
-if [[ $EUID -ne 0 ]]; then
+if [[ "${EUID}" -ne 0 ]]; then
    error "This script must be run as root (use sudo)"
 fi
 
@@ -74,7 +74,7 @@ if ! command -v node &> /dev/null; then
     log "✓ Node.js $(node -v) installed successfully"
 else
     NODE_VERSION=$(node -v | cut -d'v' -f2 | cut -d'.' -f1)
-    if [ "$NODE_VERSION" -lt 18 ]; then
+    if [ "${NODE_VERSION}" -lt 18 ]; then
         warn "Node.js version too old ($(node -v)). Upgrading to 20.x..."
         curl -fsSL https://deb.nodesource.com/setup_20.x | bash - >> "$LOG_FILE" 2>&1
         apt-get install -y nodejs >> "$LOG_FILE" 2>&1 || error "Failed to upgrade Node.js"
@@ -100,7 +100,7 @@ if ! command -v pnpm &> /dev/null; then
     log "✓ pnpm $(pnpm -v) installed successfully"
 else
     PNPM_VERSION=$(pnpm -v | cut -d'.' -f1)
-    if [ "$PNPM_VERSION" -lt 8 ]; then
+    if [ "${PNPM_VERSION}" -lt 8 ]; then
         warn "pnpm version too old ($(pnpm -v)). Upgrading to 8.15.0..."
         npm install -g pnpm@8.15.0 >> "$LOG_FILE" 2>&1 || error "Failed to upgrade pnpm"
         log "✓ pnpm upgraded to $(pnpm -v)"
@@ -154,16 +154,16 @@ fi
 
 # Use pnpm for monorepo
 PKG_MANAGER="pnpm"
-log "✓ Package manager: $PKG_MANAGER"
+log "✓ Package manager: ${PKG_MANAGER}"
 
 # Step 2: Setup PostgreSQL with Docker
 log "Step 2/8: Setting up PostgreSQL with Docker..."
 
 # Stop and remove existing container if exists
-if docker ps -a | grep -q $DB_CONTAINER_NAME; then
+if docker ps -a | grep -q "${DB_CONTAINER_NAME}"; then
     log "Removing existing PostgreSQL container..."
-    docker stop $DB_CONTAINER_NAME 2>/dev/null || true
-    docker rm $DB_CONTAINER_NAME 2>/dev/null || true
+    docker stop "${DB_CONTAINER_NAME}" 2>/dev/null || true
+    docker rm "${DB_CONTAINER_NAME}" 2>/dev/null || true
 fi
 
 # Remove old volume to ensure clean installation
@@ -181,41 +181,41 @@ fi
 # Start PostgreSQL container
 log "Starting PostgreSQL container..."
 docker run -d \
-    --name $DB_CONTAINER_NAME \
+    --name "${DB_CONTAINER_NAME}" \
     --network nginx-love-network \
-    -e POSTGRES_DB=$DB_NAME \
-    -e POSTGRES_USER=$DB_USER \
-    -e POSTGRES_PASSWORD=$DB_PASSWORD \
-    -p 127.0.0.1:$DB_PORT:5432 \
+    -e POSTGRES_DB="${DB_NAME}" \
+    -e POSTGRES_USER="${DB_USER}" \
+    -e POSTGRES_PASSWORD="${DB_PASSWORD}" \
+    -p 127.0.0.1:"${DB_PORT}":5432 \
     -v nginx-love-postgres-data:/var/lib/postgresql/data \
     --restart unless-stopped \
-    postgres:15-alpine >> "$LOG_FILE" 2>&1 || error "Failed to start PostgreSQL container"
+    postgres:15-alpine >> "${LOG_FILE}" 2>&1 || error "Failed to start PostgreSQL container"
 
 # Wait for PostgreSQL to be ready
 log "Waiting for PostgreSQL to be ready..."
 sleep 5
 for i in {1..30}; do
-    if docker exec $DB_CONTAINER_NAME pg_isready -U $DB_USER > /dev/null 2>&1; then
+    if docker exec "${DB_CONTAINER_NAME}" pg_isready -U "${DB_USER}" > /dev/null 2>&1; then
         log "✓ PostgreSQL is ready"
         break
     fi
-    if [ $i -eq 30 ]; then
+    if [ "${i}" -eq 30 ]; then
         error "PostgreSQL failed to start"
     fi
     sleep 1
 done
 
 log "✓ PostgreSQL container started successfully"
-log "  • Database: $DB_NAME"
-log "  • User: $DB_USER"
-log "  • Port: $DB_PORT"
+log "  • Database: ${DB_NAME}"
+log "  • User: ${DB_USER}"
+log "  • Port: ${DB_PORT}"
 
 # Step 3: Install Nginx + ModSecurity
 log "Step 3/8: Installing Nginx + ModSecurity..."
 
 if ! command -v nginx &> /dev/null; then
     info "Nginx not found. Installing..."
-    bash "$PROJECT_DIR/scripts/install-nginx-modsecurity.sh" || error "Failed to install Nginx + ModSecurity"
+    bash "${PROJECT_DIR}/scripts/install-nginx-modsecurity.sh" || error "Failed to install Nginx + ModSecurity"
     log "✓ Nginx + ModSecurity installed"
 else
     log "✓ Nginx already installed ($(nginx -v 2>&1 | cut -d'/' -f2))"
@@ -225,40 +225,40 @@ fi
 log "Step 4/8: Setting up Backend..."
 
 # Install root dependencies first (for monorepo)
-cd "$PROJECT_DIR"
+cd "${PROJECT_DIR}"
 if [ ! -d "node_modules" ]; then
     log "Installing monorepo dependencies..."
-    $PKG_MANAGER install >> "$LOG_FILE" 2>&1 || error "Failed to install monorepo dependencies"
+    "${PKG_MANAGER}" install >> "${LOG_FILE}" 2>&1 || error "Failed to install monorepo dependencies"
 else
     log "✓ Monorepo dependencies already installed"
 fi
 
-cd "$BACKEND_DIR"
+cd "${BACKEND_DIR}"
 
 # Create backend .env from .env.example (always create fresh)
 log "Creating fresh backend .env from .env.example..."
 cat > ".env" <<EOF
 # Database Configuration
-DATABASE_URL="postgresql://$DB_USER:$DB_PASSWORD@localhost:$DB_PORT/$DB_NAME?schema=public"
+DATABASE_URL="postgresql://${DB_USER}:${DB_PASSWORD}@localhost:${DB_PORT}/${DB_NAME}?schema=public"
 
 # Server Configuration
 PORT=3001
 NODE_ENV="production"
 
 # JWT Configuration
-JWT_ACCESS_SECRET="$JWT_ACCESS_SECRET"
-JWT_REFRESH_SECRET="$JWT_REFRESH_SECRET"
+JWT_ACCESS_SECRET="${JWT_ACCESS_SECRET}"
+JWT_REFRESH_SECRET="${JWT_REFRESH_SECRET}"
 JWT_ACCESS_EXPIRES_IN=15m
 JWT_REFRESH_EXPIRES_IN=7d
 
 # CORS Configuration (comma-separated origins)
-CORS_ORIGIN="http://$PUBLIC_IP:8080,http://localhost:8080,http://localhost:5173,http://$PUBLIC_IP,http://localhost"
+CORS_ORIGIN="http://${PUBLIC_IP}:8080,http://localhost:8080,http://localhost:5173,http://${PUBLIC_IP},http://localhost"
 
 # Security
 BCRYPT_ROUNDS=10
 
 # Session
-SESSION_SECRET="$SESSION_SECRET"
+SESSION_SECRET="${SESSION_SECRET}"
 
 # 2FA
 TWO_FACTOR_APP_NAME="Nginx Love UI"
@@ -278,7 +278,7 @@ log "✅ Created fresh backend .env"
 
 log "✓ Backend .env configured with:"
 log "  • Database: PostgreSQL (Docker)"
-log "  • CORS Origins: $PUBLIC_IP, localhost"
+log "  • CORS Origins: ${PUBLIC_IP}, localhost"
 log "  • JWT Secrets: Generated (64 chars each)"
 
 # Generate Prisma Client
@@ -299,24 +299,24 @@ log "✓ Backend setup completed"
 
 # Step 5: Build Backend
 log "Step 5/8: Building Backend..."
-cd "$PROJECT_DIR"
-pnpm --filter @nginx-love/api build >> "$LOG_FILE" 2>&1 || error "Failed to build backend"
+cd "${PROJECT_DIR}"
+pnpm --filter @nginx-love/api build >> "${LOG_FILE}" 2>&1 || error "Failed to build backend"
 log "✓ Backend built successfully"
 
 # Step 6: Setup Frontend
 log "Step 6/8: Setting up Frontend..."
 
-cd "$FRONTEND_DIR"
+cd "${FRONTEND_DIR}"
 
 # Create frontend .env from .env.example (always create fresh)
 log "Creating fresh frontend .env from .env.example..."
 cat > ".env" <<EOF
-VITE_API_URL=http://$PUBLIC_IP:3001/api
+VITE_API_URL=http://${PUBLIC_IP}:3001/api
 EOF
 
 log "✅ Created fresh frontend .env"
 
-log "✓ Frontend .env configured with API: http://$PUBLIC_IP:3001/api"
+log "✓ Frontend .env configured with API: http://${PUBLIC_IP}:3001/api"
 
 # Clean previous build
 if [ -d "dist" ]; then
@@ -326,16 +326,16 @@ fi
 
 # Build frontend
 log "Building frontend..."
-cd "$PROJECT_DIR"
-pnpm --filter @nginx-love/web build >> "$LOG_FILE" 2>&1 || error "Failed to build frontend"
+cd "${PROJECT_DIR}"
+pnpm --filter @nginx-love/web build >> "${LOG_FILE}" 2>&1 || error "Failed to build frontend"
 
 # Update CSP in built index.html to use public IP
 log "Updating Content Security Policy with public IP..."
-sed -i "s|__API_URL__|http://$PUBLIC_IP:3001 http://localhost:3001|g" "$FRONTEND_DIR/dist/index.html"
-sed -i "s|__WS_URL__|ws://$PUBLIC_IP:* ws://localhost:*|g" "$FRONTEND_DIR/dist/index.html"
+sed -i "s|__API_URL__|http://${PUBLIC_IP}:3001 http://localhost:3001|g" "${FRONTEND_DIR}/dist/index.html"
+sed -i "s|__WS_URL__|ws://${PUBLIC_IP}:* ws://localhost:*|g" "${FRONTEND_DIR}/dist/index.html"
 
 log "✓ Frontend built successfully"
-log "✓ CSP configured for: http://$PUBLIC_IP:3001, http://localhost:3001"
+log "✓ CSP configured for: http://${PUBLIC_IP}:3001, http://localhost:3001"
 
 # Step 7: Setup Nginx Configuration
 log "Step 7/8: Configuring Nginx..."
@@ -377,7 +377,7 @@ After=network.target postgresql.service
 [Service]
 Type=simple
 User=root
-WorkingDirectory=$BACKEND_DIR
+WorkingDirectory=${BACKEND_DIR}
 Environment=NODE_ENV=production
 ExecStart=$(which node) dist/index.js
 Restart=always
@@ -398,7 +398,7 @@ After=network.target
 [Service]
 Type=simple
 User=root
-WorkingDirectory=$FRONTEND_DIR
+WorkingDirectory=${FRONTEND_DIR}
 Environment=NODE_ENV=production
 ExecStart=$(which pnpm) preview --host 0.0.0.0 --port 8080
 Restart=always
@@ -460,31 +460,31 @@ log "Deployment Completed Successfully!"
 log "=================================="
 log ""
 log "📋 Service Status:"
-log "  • PostgreSQL: Docker container '$DB_CONTAINER_NAME'"
-log "  • Backend API: http://$PUBLIC_IP:3001"
-log "  • Frontend UI: http://$PUBLIC_IP:8080"
+log "  • PostgreSQL: Docker container '${DB_CONTAINER_NAME}'"
+log "  • Backend API: http://${PUBLIC_IP}:3001"
+log "  • Frontend UI: http://${PUBLIC_IP}:8080"
 log "  • Nginx: Port 80/443"
 log ""
 log "🔐 Database Credentials:"
 log "  • Host: localhost"
-log "  • Port: $DB_PORT"
-log "  • Database: $DB_NAME"
-log "  • Username: $DB_USER"
-log "  • Password: $DB_PASSWORD"
+log "  • Port: ${DB_PORT}"
+log "  • Database: ${DB_NAME}"
+log "  • Username: ${DB_USER}"
+log "  • Password: ${DB_PASSWORD}"
 log ""
 log "🔑 Security Keys:"
-log "  • JWT Access Secret: $JWT_ACCESS_SECRET"
-log "  • JWT Refresh Secret: $JWT_REFRESH_SECRET"
-log "  • Session Secret: $SESSION_SECRET"
+log "  • JWT Access Secret: ${JWT_ACCESS_SECRET}"
+log "  • JWT Refresh Secret: ${JWT_REFRESH_SECRET}"
+log "  • Session Secret: ${SESSION_SECRET}"
 log ""
 log "📝 Manage Services:"
-log "  PostgreSQL: docker start|stop|restart $DB_CONTAINER_NAME"
+log "  PostgreSQL: docker start|stop|restart ${DB_CONTAINER_NAME}"
 log "  Backend:    systemctl {start|stop|restart|status} nginx-love-backend"
 log "  Frontend:   systemctl {start|stop|restart|status} nginx-love-frontend"
 log "  Nginx:      systemctl {start|stop|restart|status} nginx"
 log ""
 log "📊 View Logs:"
-log "  PostgreSQL: docker logs -f $DB_CONTAINER_NAME"
+log "  PostgreSQL: docker logs -f ${DB_CONTAINER_NAME}"
 log "  Backend:    tail -f /var/log/nginx-love-backend.log"
 log "  Frontend:   tail -f /var/log/nginx-love-frontend.log"
 log "  Nginx:      tail -f /var/log/nginx/error.log"
@@ -493,7 +493,7 @@ log "🔐 Default Credentials:"
 log "  Username: admin"
 log "  Password: admin123"
 log ""
-log "🌐 Access the portal at: http://$PUBLIC_IP:8080"
+log "🌐 Access the portal at: http://${PUBLIC_IP}:8080"
 log ""
 
 # Save credentials to file
@@ -502,31 +502,31 @@ cat > /root/.nginx-love-credentials <<EOF
 # Generated: $(date)
 
 ## Public Access
-Frontend: http://$PUBLIC_IP:8080
-Backend:  http://$PUBLIC_IP:3001
+Frontend: http://${PUBLIC_IP}:8080
+Backend:  http://${PUBLIC_IP}:3001
 
 ## Database (Docker)
-Container: $DB_CONTAINER_NAME
+Container: ${DB_CONTAINER_NAME}
 Host: localhost
-Port: $DB_PORT
-Database: $DB_NAME
-Username: $DB_USER
-Password: $DB_PASSWORD
+Port: ${DB_PORT}
+Database: ${DB_NAME}
+Username: ${DB_USER}
+Password: ${DB_PASSWORD}
 
 ## Security Keys
-JWT_ACCESS_SECRET=$JWT_ACCESS_SECRET
-JWT_REFRESH_SECRET=$JWT_REFRESH_SECRET
-SESSION_SECRET=$SESSION_SECRET
+JWT_ACCESS_SECRET=${JWT_ACCESS_SECRET}
+JWT_REFRESH_SECRET=${JWT_REFRESH_SECRET}
+SESSION_SECRET=${SESSION_SECRET}
 
 ## Default Login
 Username: admin
 Password: admin123
 
 ## Docker Commands
-Start:   docker start $DB_CONTAINER_NAME
-Stop:    docker stop $DB_CONTAINER_NAME
-Logs:    docker logs -f $DB_CONTAINER_NAME
-Connect: docker exec -it $DB_CONTAINER_NAME psql -U $DB_USER -d $DB_NAME
+Start:   docker start ${DB_CONTAINER_NAME}
+Stop:    docker stop ${DB_CONTAINER_NAME}
+Logs:    docker logs -f ${DB_CONTAINER_NAME}
+Connect: docker exec -it ${DB_CONTAINER_NAME} psql -U ${DB_USER} -d ${DB_NAME}
 EOF
 
 chmod 600 /root/.nginx-love-credentials
@@ -547,5 +547,5 @@ else
 fi
 
 log ""
-log "Deployment log saved to: $LOG_FILE"
+log "Deployment log saved to: ${LOG_FILE}"
 log "=================================="
\ No newline at end of file
diff --git a/scripts/install-nginx-modsecurity.sh b/scripts/install-nginx-modsecurity.sh
index d4f174e..3141eb3 100755
--- a/scripts/install-nginx-modsecurity.sh
+++ b/scripts/install-nginx-modsecurity.sh
@@ -25,7 +25,7 @@ NC='\033[0m' # No Color
 
 # Logging function
 log() {
-    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "$INSTALL_LOG"
+    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "${INSTALL_LOG}"
 }
 
 # Update status file
@@ -33,7 +33,7 @@ update_status() {
     local step=$1
     local status=$2
     local message=$3
-    echo "{\"step\":\"$step\",\"status\":\"$status\",\"message\":\"$message\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\"}" > "$INSTALL_STATUS_FILE"
+    echo "{\"step\":\"${step}\",\"status\":\"${status}\",\"message\":\"${message}\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\"}" > "${INSTALL_STATUS_FILE}"
 }
 
 # Error handler
@@ -44,7 +44,7 @@ error_exit() {
 }
 
 # Check if running as root
-if [[ $EUID -ne 0 ]]; then
+if [[ "${EUID}" -ne 0 ]]; then
    error_exit "This script must be run as root"
 fi
 
@@ -56,7 +56,7 @@ log "================================================"
 log "Step 1/8: Installing dependencies..."
 update_status "dependencies" "running" "Installing required packages..."
 
-apt-get update >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to update package list"
+apt-get update >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to update package list"
 
 apt-get install -y \
     build-essential \
@@ -77,7 +77,7 @@ apt-get install -y \
     autoconf \
     git \
     wget \
-    >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to install dependencies"
+    >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to install dependencies"
 
 log "Dependencies installed successfully"
 update_status "dependencies" "completed" "All dependencies installed"
@@ -88,7 +88,7 @@ update_status "modsecurity_download" "running" "Downloading ModSecurity..."
 
 cd /usr/local/src
 if [ ! -d "ModSecurity" ]; then
-    git clone --depth 1 -b v${MODSECURITY_VERSION} --single-branch https://github.com/SpiderLabs/ModSecurity >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to clone ModSecurity"
+    git clone --depth 1 -b v${MODSECURITY_VERSION} --single-branch https://github.com/SpiderLabs/ModSecurity >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to clone ModSecurity"
 fi
 
 log "ModSecurity downloaded successfully"
@@ -99,12 +99,12 @@ log "Step 3/8: Building ModSecurity..."
 update_status "modsecurity_build" "running" "Compiling ModSecurity (this may take 10-15 minutes)..."
 
 cd ModSecurity
-git submodule init >> "$INSTALL_LOG" 2>&1
-git submodule update >> "$INSTALL_LOG" 2>&1
-./build.sh >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to build ModSecurity"
-./configure >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to configure ModSecurity"
-make -j$(nproc) >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to compile ModSecurity"
-make install >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to install ModSecurity"
+git submodule init >> "${INSTALL_LOG}" 2>&1
+git submodule update >> "${INSTALL_LOG}" 2>&1
+./build.sh >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to build ModSecurity"
+./configure >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to configure ModSecurity"
+make -j$(nproc) >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to compile ModSecurity"
+make install >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to install ModSecurity"
 
 log "ModSecurity built and installed successfully"
 update_status "modsecurity_build" "completed" "ModSecurity compiled and installed"
@@ -115,7 +115,7 @@ update_status "connector_download" "running" "Downloading ModSecurity-nginx conn
 
 cd /usr/local/src
 if [ ! -d "ModSecurity-nginx" ]; then
-    git clone --depth 1 https://github.com/SpiderLabs/ModSecurity-nginx.git >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to clone ModSecurity-nginx"
+    git clone --depth 1 https://github.com/SpiderLabs/ModSecurity-nginx.git >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to clone ModSecurity-nginx"
 fi
 
 log "ModSecurity-nginx connector downloaded"
@@ -127,8 +127,8 @@ update_status "nginx_download" "running" "Downloading Nginx..."
 
 cd /usr/local/src
 if [ ! -f "nginx-${NGINX_VERSION}.tar.gz" ]; then
-    wget http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to download Nginx"
-    tar -xzf nginx-${NGINX_VERSION}.tar.gz >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to extract Nginx"
+    wget http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to download Nginx"
+    tar -xzf nginx-${NGINX_VERSION}.tar.gz >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to extract Nginx"
 fi
 
 log "Nginx downloaded successfully"
@@ -173,10 +173,10 @@ cd nginx-${NGINX_VERSION}
     --with-http_slice_module \
     --with-file-aio \
     --add-dynamic-module=/usr/local/src/ModSecurity-nginx \
-    >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to configure Nginx"
+    >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to configure Nginx"
 
-make -j$(nproc) >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to compile Nginx"
-make install >> "$INSTALL_LOG" 2>&1 || error_exit "Failed to install Nginx"
+make -j$(nproc) >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to compile Nginx"
+make install >> "${INSTALL_LOG}" 2>&1 || error_exit "Failed to install Nginx"
 
 # Copy ModSecurity dynamic module to nginx modules directory
 mkdir -p /usr/lib/nginx/modules
@@ -191,26 +191,26 @@ log "Step 7/8: Configuring ModSecurity..."
 update_status "modsecurity_config" "running" "Setting up ModSecurity configuration..."
 
 # Create ModSecurity directories
-mkdir -p "$MODSECURITY_CONFIG_DIR"
+mkdir -p "${MODSECURITY_CONFIG_DIR}"
 mkdir -p /var/log/modsec
 
 # Copy ModSecurity configuration
-cp /usr/local/src/ModSecurity/modsecurity.conf-recommended "$MODSECURITY_CONFIG_DIR/modsecurity.conf"
-cp /usr/local/src/ModSecurity/unicode.mapping "$MODSECURITY_CONFIG_DIR/"
+cp /usr/local/src/ModSecurity/modsecurity.conf-recommended "${MODSECURITY_CONFIG_DIR}/modsecurity.conf"
+cp /usr/local/src/ModSecurity/unicode.mapping "${MODSECURITY_CONFIG_DIR}/"
 
 # Enable ModSecurity
-sed -i 's/SecRuleEngine DetectionOnly/SecRuleEngine On/' "$MODSECURITY_CONFIG_DIR/modsecurity.conf"
+sed -i 's/SecRuleEngine DetectionOnly/SecRuleEngine On/' "${MODSECURITY_CONFIG_DIR}/modsecurity.conf"
 
 # Download OWASP Core Rule Set
-cd "$MODSECURITY_CONFIG_DIR"
+cd "${MODSECURITY_CONFIG_DIR}"
 if [ ! -d "coreruleset" ]; then
-    git clone https://github.com/coreruleset/coreruleset.git >> "$INSTALL_LOG" 2>&1
+    git clone https://github.com/coreruleset/coreruleset.git >> "${INSTALL_LOG}" 2>&1
     cd coreruleset
     mv crs-setup.conf.example crs-setup.conf
 fi
 
 # Create main ModSecurity configuration
-cat > "$MODSECURITY_CONFIG_DIR/main.conf" << 'EOF'
+cat > "${MODSECURITY_CONFIG_DIR}/main.conf" << 'EOF'
 Include /etc/nginx/modsec/modsecurity.conf
 Include /etc/nginx/modsec/coreruleset/crs-setup.conf
 Include /etc/nginx/modsec/coreruleset/rules/*.conf
@@ -370,11 +370,11 @@ EOF
 
 # Enable and start nginx
 systemctl daemon-reload
-systemctl enable nginx >> "$INSTALL_LOG" 2>&1
-systemctl start nginx >> "$INSTALL_LOG" 2>&1
+systemctl enable nginx >> "${INSTALL_LOG}" 2>&1
+systemctl start nginx >> "${INSTALL_LOG}" 2>&1
 
 # Test nginx
-if nginx -t >> "$INSTALL_LOG" 2>&1; then
+if nginx -t >> "${INSTALL_LOG}" 2>&1; then
     log "Nginx configuration test passed"
 else
     error_exit "Nginx configuration test failed"
diff --git a/scripts/quickstart.sh b/scripts/quickstart.sh
index 6fdd9f4..a4de69f 100755
--- a/scripts/quickstart.sh
+++ b/scripts/quickstart.sh
@@ -14,9 +14,9 @@ NC='\033[0m'
 
 # Paths
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-PROJECT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
-BACKEND_DIR="$PROJECT_DIR/apps/api"
-FRONTEND_DIR="$PROJECT_DIR/apps/web"
+PROJECT_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
+BACKEND_DIR="${PROJECT_DIR}/apps/api"
+FRONTEND_DIR="${PROJECT_DIR}/apps/web"
 
 # Database config
 DB_NAME="nginx_love_db"
@@ -32,13 +32,13 @@ echo ""
 USE_DOCKER=false
 if command -v docker &> /dev/null && command -v docker-compose &> /dev/null; then
     read -p "Use Docker for PostgreSQL? (y/n, default: y): " USE_DOCKER_INPUT
-    if [ "$USE_DOCKER_INPUT" != "n" ]; then
+    if [ "${USE_DOCKER_INPUT}" != "n" ]; then
         USE_DOCKER=true
     fi
 fi
 
 # Setup PostgreSQL
-if [ "$USE_DOCKER" = true ]; then
+if [ "${USE_DOCKER}" = true ]; then
     echo "🐳 Starting PostgreSQL with Docker..."
     
     # Stop existing container if any
@@ -48,56 +48,56 @@ if [ "$USE_DOCKER" = true ]; then
     # Start PostgreSQL
     docker run -d \
         --name nginx-love-postgres \
-        -e POSTGRES_DB=$DB_NAME \
-        -e POSTGRES_USER=$DB_USER \
-        -e POSTGRES_PASSWORD=$DB_PASSWORD \
-        -p $DB_PORT:5432 \
+        -e POSTGRES_DB="${DB_NAME}" \
+        -e POSTGRES_USER="${DB_USER}" \
+        -e POSTGRES_PASSWORD="${DB_PASSWORD}" \
+        -p "${DB_PORT}":5432 \
         postgres:15-alpine > /dev/null
     
     echo "✅ PostgreSQL started in Docker"
     echo "   Waiting for database to be ready..."
     sleep 3
     
-    DATABASE_URL="postgresql://$DB_USER:$DB_PASSWORD@localhost:$DB_PORT/$DB_NAME?schema=public"
+    DATABASE_URL="postgresql://${DB_USER}:${DB_PASSWORD}@localhost:${DB_PORT}/${DB_NAME}?schema=public"
 else
     echo "📋 Please ensure PostgreSQL is running and update DATABASE_URL in backend/.env"
     DATABASE_URL=${DATABASE_URL:-"postgresql://user:password@localhost:5432/nginx_love_db?schema=public"}
 fi
 
 # Create backend .env from .env.example
-if [ ! -f "$BACKEND_DIR/.env" ]; then
+if [ ! -f "${BACKEND_DIR}/.env" ]; then
     echo "⚠️  Backend .env not found. Creating from .env.example..."
-    cp "$BACKEND_DIR/.env.example" "$BACKEND_DIR/.env"
+    cp "${BACKEND_DIR}/.env.example" "${BACKEND_DIR}/.env"
 
     # Replace with actual values
-    sed -i.bak "s|DATABASE_URL=.*|DATABASE_URL=\"$DATABASE_URL\"|g" "$BACKEND_DIR/.env"
-    sed -i.bak "s|CORS_ORIGIN=.*|CORS_ORIGIN=\"http://localhost:8080,http://localhost:5173\"|g" "$BACKEND_DIR/.env"
-    sed -i.bak "s|NODE_ENV=.*|NODE_ENV=development|g" "$BACKEND_DIR/.env"
-    rm -f "$BACKEND_DIR/.env.bak"
+    sed -i.bak "s|DATABASE_URL=.*|DATABASE_URL=\"${DATABASE_URL}\"|g" "${BACKEND_DIR}/.env"
+    sed -i.bak "s|CORS_ORIGIN=.*|CORS_ORIGIN=\"http://localhost:8080,http://localhost:5173\"|g" "${BACKEND_DIR}/.env"
+    sed -i.bak "s|NODE_ENV=.*|NODE_ENV=development|g" "${BACKEND_DIR}/.env"
+    rm -f "${BACKEND_DIR}/.env.bak"
 
-    echo "✅ Created $BACKEND_DIR/.env"
+    echo "✅ Created ${BACKEND_DIR}/.env"
 fi
 
 # Create frontend .env from .env.example
-if [ ! -f "$FRONTEND_DIR/.env" ]; then
+if [ ! -f "${FRONTEND_DIR}/.env" ]; then
     echo "⚠️  Frontend .env not found. Creating from .env.example..."
-    cp "$FRONTEND_DIR/.env.example" "$FRONTEND_DIR/.env"
+    cp "${FRONTEND_DIR}/.env.example" "${FRONTEND_DIR}/.env"
 
     # Replace with actual values
-    sed -i.bak "s|VITE_API_URL=.*|VITE_API_URL=http://localhost:3001/api|g" "$FRONTEND_DIR/.env"
-    sed -i.bak "s|VITE_DEMO_MODE=.*|VITE_DEMO_MODE=true|g" "$FRONTEND_DIR/.env"
-    rm -f "$FRONTEND_DIR/.env.bak"
+    sed -i.bak "s|VITE_API_URL=.*|VITE_API_URL=http://localhost:3001/api|g" "${FRONTEND_DIR}/.env"
+    sed -i.bak "s|VITE_DEMO_MODE=.*|VITE_DEMO_MODE=true|g" "${FRONTEND_DIR}/.env"
+    rm -f "${FRONTEND_DIR}/.env.bak"
 
-    echo "✅ Created $FRONTEND_DIR/.env"
+    echo "✅ Created ${FRONTEND_DIR}/.env"
 fi
 
 # Install dependencies
 echo "📦 Installing dependencies..."
-cd "$PROJECT_DIR" && pnpm install
+cd "${PROJECT_DIR}" && pnpm install
 
 # Setup database
 echo "🗄️  Setting up database..."
-cd "$BACKEND_DIR"
+cd "${BACKEND_DIR}"
 pnpm prisma:generate
 pnpm exec prisma migrate deploy
 pnpm prisma:seed 2>/dev/null || echo "Database already seeded"
@@ -107,20 +107,20 @@ echo "🎯 Starting services..."
 echo ""
 
 # Start backend in background
-cd "$BACKEND_DIR" && pnpm dev > /tmp/backend.log 2>&1 &
+cd "${BACKEND_DIR}" && pnpm dev > /tmp/backend.log 2>&1 &
 BACKEND_PID=$!
-echo "✅ Backend started (PID: $BACKEND_PID) - http://localhost:3001"
+echo "✅ Backend started (PID: ${BACKEND_PID}) - http://localhost:3001"
 
 # Store the process group ID for better signal handling
-BACKEND_PGID=$(ps -o pgid= -p $BACKEND_PID | tr -d ' ')
+BACKEND_PGID=$(ps -o pgid= -p "${BACKEND_PID}" | tr -d ' ')
 
 # Start frontend in background
-cd "$FRONTEND_DIR" && pnpm dev > /tmp/frontend.log 2>&1 &
+cd "${FRONTEND_DIR}" && pnpm dev > /tmp/frontend.log 2>&1 &
 FRONTEND_PID=$!
-echo "✅ Frontend started (PID: $FRONTEND_PID) - http://localhost:8080"
+echo "✅ Frontend started (PID: ${FRONTEND_PID}) - http://localhost:8080"
 
 # Store the process group ID for better signal handling
-FRONTEND_PGID=$(ps -o pgid= -p $FRONTEND_PID | tr -d ' ')
+FRONTEND_PGID=$(ps -o pgid= -p "${FRONTEND_PID}" | tr -d ' ')
 
 echo ""
 echo "================================"
@@ -140,10 +140,10 @@ echo "   Backend:  tail -f /tmp/backend.log"
 echo "   Frontend: tail -f /tmp/frontend.log"
 echo ""
 echo "🛑 Stop:"
-if [ "$USE_DOCKER" = true ]; then
-    echo "   kill $BACKEND_PID $FRONTEND_PID && docker stop nginx-love-postgres"
+if [ "${USE_DOCKER}" = true ]; then
+    echo "   kill ${BACKEND_PID} ${FRONTEND_PID} && docker stop nginx-love-postgres"
 else
-    echo "   kill $BACKEND_PID $FRONTEND_PID"
+    echo "   kill ${BACKEND_PID} ${FRONTEND_PID}"
 fi
 echo ""
 
@@ -169,19 +169,19 @@ cleanup() {
     # Method 1: Kill by port (most reliable for Node.js processes)
     echo "🔍 Stopping backend on port 3001..."
     BACKEND_PORT_PIDS=$(lsof -ti:3001 2>/dev/null)
-    if [ -n "$BACKEND_PORT_PIDS" ]; then
-        echo "🔍 Found backend processes: $BACKEND_PORT_PIDS"
-        for pid in $BACKEND_PORT_PIDS; do
+    if [ -n "${BACKEND_PORT_PIDS}" ]; then
+        echo "🔍 Found backend processes: ${BACKEND_PORT_PIDS}"
+        for pid in ${BACKEND_PORT_PIDS}; do
             # Get the full command to verify it's our Node.js process
-            CMD=$(ps -p $pid -o cmd= 2>/dev/null)
-            if [[ "$CMD" == *"node"* ]]; then
-                echo "🔍 Stopping Node.js process $pid..."
-                kill -TERM $pid 2>/dev/null
+            CMD=$(ps -p "${pid}" -o cmd= 2>/dev/null)
+            if [[ "${CMD}" == *"node"* ]]; then
+                echo "🔍 Stopping Node.js process ${pid}..."
+                kill -TERM "${pid}" 2>/dev/null
                 sleep 1
                 # Check if still running and force kill if needed
-                if kill -0 $pid 2>/dev/null; then
+                if kill -0 "${pid}" 2>/dev/null; then
                     echo "🔍 Process still running, sending SIGKILL..."
-                    kill -KILL $pid 2>/dev/null
+                    kill -KILL "${pid}" 2>/dev/null
                 fi
             fi
         done
@@ -190,50 +190,50 @@ cleanup() {
 
     echo "🔍 Stopping frontend on port 8080..."
     FRONTEND_PORT_PIDS=$(lsof -ti:8080 2>/dev/null)
-    if [ -n "$FRONTEND_PORT_PIDS" ]; then
-        for pid in $FRONTEND_PORT_PIDS; do
-            kill -TERM $pid 2>/dev/null
+    if [ -n "${FRONTEND_PORT_PIDS}" ]; then
+        for pid in ${FRONTEND_PORT_PIDS}; do
+            kill -TERM "${pid}" 2>/dev/null
             sleep 1
-            if kill -0 $pid 2>/dev/null; then
-                kill -KILL $pid 2>/dev/null
+            if kill -0 "${pid}" 2>/dev/null; then
+                kill -KILL "${pid}" 2>/dev/null
             fi
         done
         echo "✅ Frontend on port 8080 stopped"
     fi
 
     # Method 2: Kill process groups (as backup)
-    if [ -n "$BACKEND_PGID" ]; then
-        echo "🔍 Stopping backend process group (PGID: $BACKEND_PGID)..."
-        kill -TERM -$BACKEND_PGID 2>/dev/null
+    if [ -n "${BACKEND_PGID}" ]; then
+        echo "🔍 Stopping backend process group (PGID: ${BACKEND_PGID})..."
+        kill -TERM -"${BACKEND_PGID}" 2>/dev/null
         sleep 1
-        if kill -0 -$BACKEND_PGID 2>/dev/null; then
-            kill -KILL -$BACKEND_PGID 2>/dev/null
+        if kill -0 -"${BACKEND_PGID}" 2>/dev/null; then
+            kill -KILL -"${BACKEND_PGID}" 2>/dev/null
         fi
     fi
 
-    if [ -n "$FRONTEND_PGID" ]; then
-        echo "🔍 Stopping frontend process group (PGID: $FRONTEND_PGID)..."
-        kill -TERM -$FRONTEND_PGID 2>/dev/null
+    if [ -n "${FRONTEND_PGID}" ]; then
+        echo "🔍 Stopping frontend process group (PGID: ${FRONTEND_PGID})..."
+        kill -TERM -"${FRONTEND_PGID}" 2>/dev/null
         sleep 1
-        if kill -0 -$FRONTEND_PGID 2>/dev/null; then
-            kill -KILL -$FRONTEND_PGID 2>/dev/null
+        if kill -0 -"${FRONTEND_PGID}" 2>/dev/null; then
+            kill -KILL -"${FRONTEND_PGID}" 2>/dev/null
         fi
     fi
 
     # Method 3: Kill parent PIDs (as final backup)
-    if [ -n "$BACKEND_PID" ]; then
-        kill -TERM $BACKEND_PID 2>/dev/null
+    if [ -n "${BACKEND_PID}" ]; then
+        kill -TERM "${BACKEND_PID}" 2>/dev/null
         sleep 1
-        if kill -0 $BACKEND_PID 2>/dev/null; then
-            kill -KILL $BACKEND_PID 2>/dev/null
+        if kill -0 "${BACKEND_PID}" 2>/dev/null; then
+            kill -KILL "${BACKEND_PID}" 2>/dev/null
         fi
     fi
 
-    if [ -n "$FRONTEND_PID" ]; then
-        kill -TERM $FRONTEND_PID 2>/dev/null
+    if [ -n "${FRONTEND_PID}" ]; then
+        kill -TERM "${FRONTEND_PID}" 2>/dev/null
         sleep 1
-        if kill -0 $FRONTEND_PID 2>/dev/null; then
-            kill -KILL $FRONTEND_PID 2>/dev/null
+        if kill -0 "${FRONTEND_PID}" 2>/dev/null; then
+            kill -KILL "${FRONTEND_PID}" 2>/dev/null
         fi
     fi
 
@@ -241,21 +241,21 @@ cleanup() {
     sleep 1
     REMAINING_BACKEND=$(lsof -ti:3001 2>/dev/null)
     REMAINING_FRONTEND=$(lsof -ti:8080 2>/dev/null)
-    if [ -n "$REMAINING_BACKEND" ] || [ -n "$REMAINING_FRONTEND" ]; then
+    if [ -n "${REMAINING_BACKEND}" ] || [ -n "${REMAINING_FRONTEND}" ]; then
         echo "⚠️  Warning: Some processes still running:"
-        [ -n "$REMAINING_BACKEND" ] && echo "   Backend on port 3001: $REMAINING_BACKEND"
-        [ -n "$REMAINING_FRONTEND" ] && echo "   Frontend on port 8080: $REMAINING_FRONTEND"
+        [ -n "${REMAINING_BACKEND}" ] && echo "   Backend on port 3001: ${REMAINING_BACKEND}"
+        [ -n "${REMAINING_FRONTEND}" ] && echo "   Frontend on port 8080: ${REMAINING_FRONTEND}"
         echo "🔍 Force killing all remaining processes..."
-        for pid in $REMAINING_BACKEND; do
-            kill -KILL $pid 2>/dev/null
+        for pid in ${REMAINING_BACKEND}; do
+            kill -KILL "${pid}" 2>/dev/null
         done
-        for pid in $REMAINING_FRONTEND; do
-            kill -KILL $pid 2>/dev/null
+        for pid in ${REMAINING_FRONTEND}; do
+            kill -KILL "${pid}" 2>/dev/null
         done
     fi
 
     # Stop Docker PostgreSQL if used
-    if [ "$USE_DOCKER" = true ]; then
+    if [ "${USE_DOCKER}" = true ]; then
         docker stop nginx-love-postgres 2>/dev/null && echo "✅ PostgreSQL stopped"
     fi
 
diff --git a/scripts/start.sh b/scripts/start.sh
index 875fb93..6160596 100755
--- a/scripts/start.sh
+++ b/scripts/start.sh
@@ -15,22 +15,22 @@ NC='\033[0m' # No Color
 
 # Paths
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-PROJECT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
-BACKEND_DIR="$PROJECT_DIR/apps/api"
-FRONTEND_DIR="$PROJECT_DIR/apps/web"
+PROJECT_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
+BACKEND_DIR="${PROJECT_DIR}/apps/api"
+FRONTEND_DIR="${PROJECT_DIR}/apps/web"
 
 # Check if backend directory exists
-if [ ! -d "$BACKEND_DIR" ]; then
-    echo "❌ Backend directory not found at $BACKEND_DIR!"
+if [ ! -d "${BACKEND_DIR}" ]; then
+    echo "❌ Backend directory not found at ${BACKEND_DIR}!"
     exit 1
 fi
 
 echo -e "${BLUE}📦 Installing dependencies...${NC}"
-cd "$PROJECT_DIR" && pnpm install
+cd "${PROJECT_DIR}" && pnpm install
 
 echo ""
 echo -e "${BLUE}🗄️  Setting up database...${NC}"
-cd "$BACKEND_DIR"
+cd "${BACKEND_DIR}"
 pnpm prisma:generate
 pnpm exec prisma migrate deploy
 pnpm prisma:seed
@@ -59,22 +59,22 @@ echo "🚀 Starting services..."
 echo "================================================"
 echo ""
 echo -e "${YELLOW}Starting backend on port 3001...${NC}"
-cd "$BACKEND_DIR"
+cd "${BACKEND_DIR}"
 pnpm dev &
 BACKEND_PID=$!
 
 # Store the process group ID for better signal handling
-BACKEND_PGID=$(ps -o pgid= -p $BACKEND_PID | tr -d ' ')
+BACKEND_PGID=$(ps -o pgid= -p "${BACKEND_PID}" | tr -d ' ')
 
 sleep 3
 
 echo -e "${YELLOW}Starting frontend on port 5173...${NC}"
-cd "$FRONTEND_DIR"
+cd "${FRONTEND_DIR}"
 pnpm dev &
 FRONTEND_PID=$!
 
 # Store the process group ID for better signal handling
-FRONTEND_PGID=$(ps -o pgid= -p $FRONTEND_PID | tr -d ' ')
+FRONTEND_PGID=$(ps -o pgid= -p "${FRONTEND_PID}" | tr -d ' ')
 
 echo ""
 echo "================================================"
@@ -95,19 +95,19 @@ cleanup() {
     # Method 1: Kill by port (most reliable for Node.js processes)
     echo "🔍 Stopping backend on port 3001..."
     BACKEND_PORT_PIDS=$(lsof -ti:3001 2>/dev/null)
-    if [ -n "$BACKEND_PORT_PIDS" ]; then
-        echo "🔍 Found backend processes: $BACKEND_PORT_PIDS"
-        for pid in $BACKEND_PORT_PIDS; do
+    if [ -n "${BACKEND_PORT_PIDS}" ]; then
+        echo "🔍 Found backend processes: ${BACKEND_PORT_PIDS}"
+        for pid in ${BACKEND_PORT_PIDS}; do
             # Get the full command to verify it's our Node.js process
-            CMD=$(ps -p $pid -o cmd= 2>/dev/null)
-            if [[ "$CMD" == *"node"* ]]; then
-                echo "🔍 Stopping Node.js process $pid..."
-                kill -TERM $pid 2>/dev/null
+            CMD=$(ps -p "${pid}" -o cmd= 2>/dev/null)
+            if [[ "${CMD}" == *"node"* ]]; then
+                echo "🔍 Stopping Node.js process ${pid}..."
+                kill -TERM "${pid}" 2>/dev/null
                 sleep 1
                 # Check if still running and force kill if needed
-                if kill -0 $pid 2>/dev/null; then
+                if kill -0 "${pid}" 2>/dev/null; then
                     echo "🔍 Process still running, sending SIGKILL..."
-                    kill -KILL $pid 2>/dev/null
+                    kill -KILL "${pid}" 2>/dev/null
                 fi
             fi
         done
@@ -116,61 +116,61 @@ cleanup() {
 
     echo "🔍 Stopping frontend on port 5173..."
     FRONTEND_PORT_PIDS=$(lsof -ti:5173 2>/dev/null)
-    if [ -n "$FRONTEND_PORT_PIDS" ]; then
-        for pid in $FRONTEND_PORT_PIDS; do
-            kill -TERM $pid 2>/dev/null
+    if [ -n "${FRONTEND_PORT_PIDS}" ]; then
+        for pid in ${FRONTEND_PORT_PIDS}; do
+            kill -TERM "${pid}" 2>/dev/null
             sleep 1
-            if kill -0 $pid 2>/dev/null; then
-                kill -KILL $pid 2>/dev/null
+            if kill -0 "${pid}" 2>/dev/null; then
+                kill -KILL "${pid}" 2>/dev/null
             fi
         done
         echo "✅ Frontend on port 5173 stopped"
     fi
 
     # Method 2: Kill process groups (as backup)
-    if [ -n "$BACKEND_PGID" ]; then
-        echo "🔍 Stopping backend process group (PGID: $BACKEND_PGID)..."
-        kill -TERM -$BACKEND_PGID 2>/dev/null
+    if [ -n "${BACKEND_PGID}" ]; then
+        echo "🔍 Stopping backend process group (PGID: ${BACKEND_PGID})..."
+        kill -TERM -"${BACKEND_PGID}" 2>/dev/null
         sleep 1
-        if kill -0 -$BACKEND_PGID 2>/dev/null; then
-            kill -KILL -$BACKEND_PGID 2>/dev/null
+        if kill -0 -"${BACKEND_PGID}" 2>/dev/null; then
+            kill -KILL -"${BACKEND_PGID}" 2>/dev/null
         fi
     fi
 
-    if [ -n "$FRONTEND_PGID" ]; then
-        echo "🔍 Stopping frontend process group (PGID: $FRONTEND_PGID)..."
-        kill -TERM -$FRONTEND_PGID 2>/dev/null
+    if [ -n "${FRONTEND_PGID}" ]; then
+        echo "🔍 Stopping frontend process group (PGID: ${FRONTEND_PGID})..."
+        kill -TERM -"${FRONTEND_PGID}" 2>/dev/null
         sleep 1
-        if kill -0 -$FRONTEND_PGID 2>/dev/null; then
-            kill -KILL -$FRONTEND_PGID 2>/dev/null
+        if kill -0 -"${FRONTEND_PGID}" 2>/dev/null; then
+            kill -KILL -"${FRONTEND_PGID}" 2>/dev/null
         fi
     fi
 
     # Method 3: Kill parent PIDs (as final backup)
-    if [ -n "$BACKEND_PID" ]; then
-        kill -TERM $BACKEND_PID 2>/dev/null
+    if [ -n "${BACKEND_PID}" ]; then
+        kill -TERM "${BACKEND_PID}" 2>/dev/null
         sleep 1
-        if kill -0 $BACKEND_PID 2>/dev/null; then
-            kill -KILL $BACKEND_PID 2>/dev/null
+        if kill -0 "${BACKEND_PID}" 2>/dev/null; then
+            kill -KILL "${BACKEND_PID}" 2>/dev/null
         fi
     fi
 
-    if [ -n "$FRONTEND_PID" ]; then
-        kill -TERM $FRONTEND_PID 2>/dev/null
+    if [ -n "${FRONTEND_PID}" ]; then
+        kill -TERM "${FRONTEND_PID}" 2>/dev/null
         sleep 1
-        if kill -0 $FRONTEND_PID 2>/dev/null; then
-            kill -KILL $FRONTEND_PID 2>/dev/null
+        if kill -0 "${FRONTEND_PID}" 2>/dev/null; then
+            kill -KILL "${FRONTEND_PID}" 2>/dev/null
         fi
     fi
 
     # Final verification
     sleep 1
     REMAINING_BACKEND=$(lsof -ti:3001 2>/dev/null)
-    if [ -n "$REMAINING_BACKEND" ]; then
-        echo "⚠️  Warning: Some processes still running on port 3001: $REMAINING_BACKEND"
+    if [ -n "${REMAINING_BACKEND}" ]; then
+        echo "⚠️  Warning: Some processes still running on port 3001: ${REMAINING_BACKEND}"
         echo "🔍 Force killing all remaining processes..."
-        for pid in $REMAINING_BACKEND; do
-            kill -KILL $pid 2>/dev/null
+        for pid in ${REMAINING_BACKEND}; do
+            kill -KILL "${pid}" 2>/dev/null
         done
     fi
 
@@ -182,4 +182,4 @@ cleanup() {
 trap cleanup SIGINT SIGTERM
 
 # Wait for user to stop
-wait $BACKEND_PID $FRONTEND_PID
\ No newline at end of file
+wait "${BACKEND_PID}" "${FRONTEND_PID}"
\ No newline at end of file