diff --git a/install_offline.sh b/install_offline.sh
index 97b0541..d9c387c 100755
--- a/install_offline.sh
+++ b/install_offline.sh
@@ -1,379 +1,147 @@
-# Makefile for hdwalletpy workflow
-# - Build reusable Docker image (Python 3.12)
-# - Vendor multi-platform wheels for offline air-gapped use
-# - Compile wheels in container (wheelhouse)
-# - Create host venv and install from wheelhouse or vendor/
-# - Optionally run inside a warm container
+#!/bin/bash
+set -e
 
-# ---------- Platform Detection ----------
-UNAME_S := $(shell uname -s)
-UNAME_M := $(shell uname -m)
+# Parse arguments
+DEV_MODE=false
+if [ "$1" == "--dev" ]; then
+    DEV_MODE=true
+    echo "🛠️  Development mode enabled"
+fi
 
-ifeq ($(UNAME_S),Darwin)
-    PLATFORM := macos
-    ifeq ($(UNAME_M),arm64)
-        ARCH := arm64
+# Detect platform
+if [[ "$OSTYPE" == "linux-gnu"* ]]; then
+    PLATFORM="linux-x86_64"
+elif [[ "$OSTYPE" == "darwin"* ]]; then
+    ARCH=$(uname -m)
+    if [[ "$ARCH" == "arm64" ]]; then
+        PLATFORM="macos-arm64"
     else
-        $(error Unsupported macOS architecture: $(UNAME_M))
-    endif
-else ifeq ($(UNAME_S),Linux)
-    PLATFORM := linux
-    ARCH := x86_64
+        echo "ERROR: Only macOS ARM64 is supported"
+        exit 1
+    fi
 else
-    $(error Unsupported OS: $(UNAME_S))
-endif
+    echo "ERROR: Unsupported platform: $OSTYPE"
+    exit 1
+fi
 
-VENDOR_DIR := vendor/$(PLATFORM)-$(ARCH)
+echo "Detected platform: $PLATFORM"
 
-# ---------- Config ----------
-IMAGE := hdwallet-build:3.12
-CONTAINER := hdwallet-dev
-WORKDIR := /app
-VENV_HOST := .venv
-VENV_CONTAINER := /opt/venv
-WHEELHOUSE := wheelhouse
+# Check if vendor directory exists
+VENDOR_PATH="vendor/$PLATFORM"
+if [ "$DEV_MODE" = true ]; then
+    VENDOR_PATH="vendor/$PLATFORM-dev"
+fi
 
-# Vendor directories for air-gapped deployment
-VENDOR_MACOS := vendor/macos-arm64
-VENDOR_LINUX := vendor/linux-x86_64
+if [ ! -d "$VENDOR_PATH" ]; then
+    echo "ERROR: $VENDOR_PATH not found!"
+    if [ "$DEV_MODE" = true ]; then
+        echo "Run 'make vendor-linux-dev' to generate dev wheels"
+    else
+        echo "Run 'make vendor-linux' or 'make vendor-macos' to generate wheels"
+    fi
+    exit 1
+fi
 
-# ---------- Help ----------
-.PHONY: help
-help:
-	@echo "pyhdwallet build system (macOS + Linux compatible)"
-	@echo ""
-	@echo "📦 Vendoring (for offline/air-gapped use):"
-	@echo "  make vendor-macos         - Build macOS ARM64 wheels (requires macOS native)"
-	@echo "  make vendor-linux         - Build Linux x86_64 wheels (Docker - any OS)"
-	@echo "  make vendor-linux-dev     - Build Linux x86_64 dev wheels (includes pytest)"
-	@echo "  make vendor-all           - Build runtime wheels for both platforms"
-	@echo "  make vendor-all-dev       - Build runtime + dev wheels for all platforms"
-	@echo "  make verify-vendor        - Test offline installation from vendor/"
-	@echo ""
-	@echo "🔨 Binary Distribution:"
-	@echo "  make binary               - Build standalone binary for current platform"
-	@echo "  make binary-linux         - Build Linux binary via Docker (any OS)"
-	@echo "  make binary-all           - Build binaries for all platforms"
-	@echo ""
-	@echo "🚀 Release Management:"
-	@echo "  make release              - Build complete release (binaries + vendors + checksums)"
-	@echo "  make release-binaries     - Copy binaries to releases/vX.Y.Z/"
-	@echo "  make release-checksums    - Generate SHA256SUMS for binaries"
-	@echo "  make release-test         - Test release binaries"
-	@echo "  make clean-release        - Remove all release artifacts"
-	@echo ""
-	@echo "🛠️  Development workflow (works on macOS + Linux):"
-	@echo "  make install              - Create venv and install runtime dependencies"
-	@echo "  make install-offline      - Install runtime deps from vendor/ (offline)"
-	@echo "  make install-dev-offline  - Install runtime + dev deps from vendor/ (offline)"
-	@echo "  make test                 - Run test suite"
-	@echo "  make build-image          - Build Docker image (Python 3.12)"
-	@echo "  make wheels               - Build wheels into ./$(WHEELHOUSE)"
-	@echo "  make up                   - Start warm dev container"
-	@echo "  make shell                - Open shell in warm container"
-	@echo "  make down                 - Stop and remove dev container"
-	@echo ""
-	@echo "🧹 Cleanup:"
-	@echo "  make clean                - Remove venv, wheelhouse (keeps vendor/)"
-	@echo "  make clean-vendor         - Remove vendor/ only"
-	@echo "  make clean-release        - Remove releases/ only"
-	@echo ""
-	@echo "ℹ️  Platform Info:"
-	@echo "  make info                 - Show platform detection info"
-	@echo ""
-	@echo "Platform notes:"
-	@echo "  • vendor-macos requires native macOS (uses .venv312 with ARM64 Python)"
-	@echo "  • vendor-linux works on any platform with Docker"
-	@echo "  • vendor-linux-dev includes pytest for offline development"
-	@echo "  • binary-linux works on any platform with Docker"
-	@echo "  • All other targets work on macOS and Linux"
+# Check for Python 3.12
+if ! command -v python3.12 &> /dev/null; then
+    echo "ERROR: Python 3.12 not found!"
+    echo "Please install Python 3.12:"
+    echo "  macOS: brew install python@3.12"
+    echo "  Linux: apt-get install python3.12 python3.12-venv"
+    exit 1
+fi
 
-# ---------- Build reusable image ----------
-.PHONY: build-image
-build-image:
-	docker build -t $(IMAGE) .
-
-# ---------- Vendoring for Air-Gapped Use ----------
-.PHONY: vendor-macos
-vendor-macos: requirements.txt
-	@echo "Building macOS ARM64 wheels (native)..."
-	@if [ ! -f ".venv312/bin/pip" ]; then \
-		echo "ERROR: .venv312 not found. Create it first:"; \
-		echo "  python3.12 -m venv .venv312 && source .venv312/bin/activate"; \
-		exit 1; \
-	fi
-	mkdir -p $(VENDOR_MACOS)
-	.venv312/bin/pip download --dest $(VENDOR_MACOS) -r requirements.txt
-	cd $(VENDOR_MACOS) && shasum -a 256 *.whl > SHA256SUMS
-	@echo "✓ macOS ARM64 wheels: $(VENDOR_MACOS)/"
-
-.PHONY: vendor-linux
-vendor-linux: requirements.txt
-	@echo "Building Linux x86_64 wheels (Docker)..."
-	mkdir -p $(VENDOR_LINUX)
-	docker run --rm \
-		--platform linux/amd64 \
-		-v "$$PWD":$(WORKDIR) \
-		-w $(WORKDIR) \
-		python:3.12-slim \
-		bash -c " \
-			set -e && \
-			apt-get update -qq && apt-get install -y -qq gcc g++ make libffi-dev && \
-			pip install --upgrade pip && \
-			pip download --dest $(VENDOR_LINUX) -r requirements.txt && \
-			pip wheel --wheel-dir $(VENDOR_LINUX) --no-deps $(VENDOR_LINUX)/*.tar.gz 2>/dev/null || true && \
-			rm -f $(VENDOR_LINUX)/*.tar.gz && \
-			cd $(VENDOR_LINUX) && sha256sum *.whl > SHA256SUMS \
-		"
-	@echo "✓ Linux x86_64 wheels: $(VENDOR_LINUX)/"
-
-.PHONY: vendor-linux-dev
-vendor-linux-dev: requirements-dev.txt
-	@echo "Building Linux x86_64 dev wheels (Docker)..."
-	mkdir -p $(VENDOR_LINUX)-dev
-	docker run --rm \
-		--platform linux/amd64 \
-		-v "$$PWD":$(WORKDIR) \
-		-w $(WORKDIR) \
-		python:3.12-slim \
-		bash -c " \
-			set -e && \
-			apt-get update -qq && apt-get install -y -qq gcc g++ make libffi-dev && \
-			pip install --upgrade pip && \
-			pip download --dest $(VENDOR_LINUX)-dev -r requirements-dev.txt && \
-			pip wheel --wheel-dir $(VENDOR_LINUX)-dev --no-deps $(VENDOR_LINUX)-dev/*.tar.gz 2>/dev/null || true && \
-			rm -f $(VENDOR_LINUX)-dev/*.tar.gz && \
-			cd $(VENDOR_LINUX)-dev && sha256sum *.whl > SHA256SUMS \
-		"
-	@echo "✓ Linux x86_64 dev wheels: $(VENDOR_LINUX)-dev/"
-
-.PHONY: vendor-all
-vendor-all: vendor-macos vendor-linux
-	@echo ""
-	@echo "✓ All platforms vendored (runtime only):"
-	@echo "  macOS ARM64:  $(VENDOR_MACOS)/  ($$(ls $(VENDOR_MACOS)/*.whl 2>/dev/null | wc -l | xargs) wheels)"
-	@echo "  Linux x86_64: $(VENDOR_LINUX)/  ($$(ls $(VENDOR_LINUX)/*.whl 2>/dev/null | wc -l | xargs) wheels)"
-	@echo ""
-	@echo "Commit with: git add vendor/ && git commit -m 'vendor: update wheels'"
-
-.PHONY: vendor-all-dev
-vendor-all-dev: vendor-linux vendor-linux-dev
-	@echo ""
-	@echo "✓ All platform wheels (runtime + dev):"
-	@echo "  Linux x86_64 (runtime): $(VENDOR_LINUX)/ ($$(ls $(VENDOR_LINUX)/*.whl 2>/dev/null | wc -l | xargs) wheels)"
-	@echo "  Linux x86_64 (dev):     $(VENDOR_LINUX)-dev/ ($$(ls $(VENDOR_LINUX)-dev/*.whl 2>/dev/null | wc -l | xargs) wheels)"
-	@echo ""
-	@echo "For macOS dev wheels, run on native macOS:"
-	@echo "  python3.12 -m venv .venv312 && source .venv312/bin/activate"
-	@echo "  pip download --dest vendor/macos-arm64-dev -r requirements-dev.txt"
-
-.PHONY: verify-vendor
-verify-vendor:
-	@echo "Testing offline installation from vendor/..."
-	@bash -c ' \
-		if [[ "$$OSTYPE" == "darwin"* ]]; then \
-			PLATFORM="macos-arm64"; \
-		else \
-			PLATFORM="linux-x86_64"; \
-		fi; \
-		echo "Platform: $$PLATFORM"; \
-		python3.12 -m venv .venv-verify && \
-		source .venv-verify/bin/activate && \
-		pip install --no-index --find-links=vendor/$$PLATFORM -r requirements.txt && \
-		python src/pyhdwallet.py test && \
-		echo "" && \
-		echo "✅ Vendor installation verified!" && \
-		deactivate && \
-		rm -rf .venv-verify \
-	'
-
-# ---------- Offline Installation ----------
-.PHONY: install-offline
-install-offline:
-	@echo "Installing from vendor/ (runtime only)..."
-	@./install_offline.sh
-
-.PHONY: install-dev-offline
-install-dev-offline:
-	@echo "Installing from vendor/ (dev mode with pytest)..."
-	@./install_offline.sh --dev
-
-# ---------- Binary Building ----------
-.PHONY: binary
-binary:
-	@echo "🔨 Building binary for current platform: $(PLATFORM)-$(ARCH)..."
-ifeq ($(PLATFORM),macos)
-	@if [ ! -f "build_binary.sh" ]; then \
-		echo "❌ build_binary.sh not found!"; \
-		exit 1; \
-	fi
-	@bash build_binary.sh
+# Create venv
+VENV_DIR=".venv"
+if [ ! -d "$VENV_DIR" ] || [ ! -f "$VENV_DIR/bin/python3.12" ]; then
+    echo "Creating Python 3.12 virtual environment..."
+    python3.12 -m venv "$VENV_DIR"
+    echo "✓ Virtual environment created: $VENV_DIR"
 else
-	@echo "⚠️  For Linux native builds, use build_binary.sh directly"
-	@echo "   Or use: make binary-linux (builds via Docker)"
-endif
+    echo "Using existing venv: $VENV_DIR"
+fi
 
-.PHONY: binary-linux
-binary-linux:
-	@./build_binary_linux.sh
+# Activate venv
+source "$VENV_DIR/bin/activate"
 
-.PHONY: binary-all
-binary-all:
-	@echo "🏗️  Building binaries for all platforms..."
-	@echo ""
-	@echo "1️⃣  Building native binary..."
-	@$(MAKE) binary
-	@echo ""
-	@echo "2️⃣  Building Linux binary via Docker..."
-	@$(MAKE) binary-linux
-	@echo ""
-	@echo "✅ All binaries built:"
-	@ls -lh dist/pyhdwallet* 2>/dev/null | awk '{print "   " $$9 " (" $$5 ")"}' || echo "   No binaries found"
+# Verify Python version
+PYTHON_VERSION=$(python --version 2>&1 | grep -oE '3\.[0-9]+')
+echo "Using Python $PYTHON_VERSION from: $(which python)"
 
-# ---------- Development Workflow ----------
-.PHONY: wheels
-wheels: requirements.txt build-image
-	docker run --rm \
-		-v "$$PWD":$(WORKDIR) \
-		-w $(WORKDIR) \
-		$(IMAGE) \
-		bash -c " \
-			pip install --upgrade pip setuptools wheel && \
-			mkdir -p $(WHEELHOUSE) && \
-			pip wheel -r requirements.txt -w $(WHEELHOUSE) \
-		"
+if [[ "$PYTHON_VERSION" != "3.12" ]]; then
+    echo "ERROR: Expected Python 3.12, got $PYTHON_VERSION"
+    exit 1
+fi
 
-.PHONY: install
-install: requirements.txt
-	@if [ ! -d "$(VENV_HOST)" ]; then \
-		echo "Creating venv: $(VENV_HOST)"; \
-		python3.12 -m venv $(VENV_HOST); \
-	fi
-	. $(VENV_HOST)/bin/activate && \
-	pip install --upgrade pip && \
-	pip install -r requirements.txt && \
-	echo "✓ Virtual environment ready: $(VENV_HOST)"
+# Verify checksums
+if [ -f "$VENDOR_PATH/SHA256SUMS" ]; then
+    echo ""
+    echo "Verifying checksums..."
+    (cd "$VENDOR_PATH" && sha256sum -c SHA256SUMS --quiet) || {
+        echo "ERROR: Checksum verification failed!"
+        exit 1
+    }
+    echo "✓ Checksums verified"
+fi
 
-.PHONY: test
-test:
-	@if [ ! -d "$(VENV_HOST)" ]; then \
-		echo "ERROR: Run 'make install' first"; \
-		exit 1; \
-	fi
-	. $(VENV_HOST)/bin/activate && \
-	pytest -v tests/test_vectors.py && \
-	python src/pyhdwallet.py test
+# Install
+echo ""
+if [ "$DEV_MODE" = true ]; then
+    echo "Installing from $VENDOR_PATH (includes dev dependencies)..."
+    pip install --upgrade pip --quiet
+    pip install --no-index --find-links="$VENDOR_PATH" -r requirements-dev.txt
+else
+    echo "Installing from $VENDOR_PATH..."
+    pip install --upgrade pip --quiet
+    pip install --no-index --find-links="$VENDOR_PATH" -r requirements.txt
+fi
 
-# ---------- Warm container lifecycle ----------
-.PHONY: up
-up: build-image
-	docker run -dit \
-		-v "$$PWD":$(WORKDIR) \
-		-w $(WORKDIR) \
-		--name $(CONTAINER) \
-		$(IMAGE) \
-		bash
+# Test
+echo ""
+echo "Running tests..."
 
-.PHONY: shell
-shell:
-	docker exec -it $(CONTAINER) bash
+if [ "$DEV_MODE" = true ]; then
+    # Run full test suite if pytest available
+    if python -c "import pytest" >/dev/null 2>&1; then
+        python -m pytest -v tests/test_vectors.py || {
+            echo "ERROR: Tests failed!"
+            exit 1
+        }
+    else
+        echo "⚠️  pytest not found in dev install!"
+    fi
+else
+    # Only mention pytest in production mode
+    echo "⚠️  Skipping pytest (use --dev for full test suite)"
+fi
 
-.PHONY: down
-down:
-	- docker rm -f $(CONTAINER)
+echo ""
+echo "Running built-in smoke test..."
+python src/pyhdwallet.py test || {
+    echo "ERROR: Smoke test failed!"
+    exit 1
+}
 
-# ---------- Cleanup ----------
-.PHONY: clean-vendor
-clean-vendor:
-	rm -rf vendor/
-
-.PHONY: clean
-clean: down
-	rm -rf $(VENV_HOST) $(WHEELHOUSE) .venv-verify .venv-offline-test
-	rm -rf dist/ build/ *.spec src/pyhdwallet_frozen.py
-	find . -type d -name __pycache__ -exec rm -rf {} + 2>/dev/null || true
-	find . -type d -name "*.egg-info" -exec rm -rf {} + 2>/dev/null || true
-	# NOTE: vendor/ is kept (use 'make clean-vendor' to remove)
-
-# ---------- Platform-Aware Operations ----------
-.PHONY: info
-info:
-	@echo "Platform Information:"
-	@echo "  OS:           $(PLATFORM)"
-	@echo "  Architecture: $(ARCH)"
-	@echo "  Vendor dir:   $(VENDOR_DIR)"
-	@echo "  Python:       $(shell python3 --version 2>/dev/null || echo 'not found')"
-	@echo "  Docker:       $(shell docker --version 2>/dev/null || echo 'not found')"
-
-# ---------- Release Management ----------
-VERSION := v1.1.0
-RELEASE_DIR := releases/$(VERSION)
-
-.PHONY: release-prep
-release-prep:
-	@echo "📦 Preparing release $(VERSION)..."
-	@mkdir -p $(RELEASE_DIR)
-
-.PHONY: release-binaries
-release-binaries: release-prep binary binary-linux
-	@echo "📦 Copying binaries to $(RELEASE_DIR)..."
-	@cp dist/pyhdwallet $(RELEASE_DIR)/pyhdwallet-macos-arm64
-	@cp dist/pyhdwallet-linux $(RELEASE_DIR)/pyhdwallet-linux-x86_64
-	@echo "✅ Binaries copied"
-
-.PHONY: release-checksums
-release-checksums: release-binaries
-	@echo "🔐 Generating checksums..."
-	@cd $(RELEASE_DIR) && shasum -a 256 pyhdwallet-* > SHA256SUMS
-	@echo "✅ Checksums generated:"
-	@cat $(RELEASE_DIR)/SHA256SUMS
-
-.PHONY: release-vendors
-release-vendors: release-prep vendor-all
-	@echo "📦 Copying vendor wheels to $(RELEASE_DIR)..."
-	@mkdir -p $(RELEASE_DIR)/vendor
-	@cp -r vendor/macos-arm64 $(RELEASE_DIR)/vendor/
-	@cp -r vendor/linux-x86_64 $(RELEASE_DIR)/vendor/
-	@echo "✅ Vendor wheels copied"
-
-.PHONY: release
-release: release-checksums
-	@echo ""
-	@echo "🎉 Release $(VERSION) binaries ready!"
-	@echo ""
-	@if [ -d ".venv312" ]; then \
-		echo "📦 Building vendor wheels..."; \
-		$(MAKE) release-vendors; \
-	else \
-		echo "⚠️  Skipping vendor wheels (.venv312 not found)"; \
-		echo "   To include vendors: python3.12 -m venv .venv312 && make release-vendors"; \
-	fi
-	@echo ""
-	@echo "Contents:"
-	@ls -lh $(RELEASE_DIR)/ | tail -n +2
-	@echo ""
-	@cat $(RELEASE_DIR)/SHA256SUMS
-	@echo ""
-	@echo "Next steps:"
-	@echo "  1. Test: make release-test"
-	@echo "  2. Tag: git tag -a $(VERSION) -m 'Release $(VERSION)'"
-	@echo "  3. Push: git push origin $(VERSION)"
-
-.PHONY: release-test
-release-test:
-	@echo "🧪 Testing release binaries..."
-	@echo ""
-	@echo "Testing macOS binary:"
-	@$(RELEASE_DIR)/pyhdwallet-macos-arm64 test || echo "⚠️  macOS binary test skipped (wrong platform)"
-	@echo ""
-	@echo "Testing Linux binary (via Docker):"
-	@docker run --rm --platform linux/amd64 \
-		-v "$$PWD/$(RELEASE_DIR)":/binaries \
-		ubuntu:22.04 \
-		/binaries/pyhdwallet-linux-x86_64 test
-
-.PHONY: clean-release
-clean-release:
-	@echo "🧹 Cleaning release artifacts..."
-	@rm -rf releases/
-	@echo "✅ Release artifacts cleaned"
+echo ""
+echo "=========================================="
+echo "✓ Installation complete and verified!"
+echo "=========================================="
+echo ""
+echo "Virtual environment: $VENV_DIR"
+echo "Python version: $(python --version)"
+if [ "$DEV_MODE" = true ]; then
+    echo "Mode: Development (pytest installed)"
+else
+    echo "Mode: Production (runtime only)"
+fi
+echo ""
+echo "To activate this environment:"
+echo "  source $VENV_DIR/bin/activate"
+echo ""
+if [ "$DEV_MODE" = false ]; then
+    echo "For development with pytest:"
+    echo "  ./install_offline.sh --dev"
+    echo ""
+fi
+echo "Generate a wallet:"
+echo "  python src/pyhdwallet.py gen --help"