diff --git a/.gitea/workflows/build-deploy.yml b/.gitea/workflows/build-deploy.yml
new file mode 100644
index 0000000..bbf283f
--- /dev/null
+++ b/.gitea/workflows/build-deploy.yml
@@ -0,0 +1,47 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Gitea Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: code.puffinoffset.com
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: code.puffinoffset.com/matt/puffin-app
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=sha,prefix={{branch}}-
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=registry,ref=code.puffinoffset.com/matt/puffin-app:buildcache
+          cache-to: type=registry,ref=code.puffinoffset.com/matt/puffin-app:buildcache,mode=max
+
+      - name: Image digest
+        run: echo "Image pushed with digest ${{ steps.build.outputs.digest }}"
diff --git a/CLAUDE.md b/CLAUDE.md
index 07a692e..ac9dc07 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -92,11 +92,58 @@ VITE_FORMSPREE_OFFSET_ID=    # Offset order form endpoint
 
 ### Testing Strategy
 - Unit tests using Vitest and React Testing Library
-- Test files in `__tests__` directories
-- Run with `npm test`
+- Test configuration in `vitest.config.ts` with jsdom environment
+- Setup file at `src/test/setup.ts`
+- Test files use pattern `*.test.ts` or `*.test.tsx`
+- Run all tests: `npm test`
+- Tests run with global test APIs enabled
 
 ### Build & Deployment
-- Production builds output to `dist/`
+- Production builds output to `dist/` directory
+- Vite build configuration includes:
+  - Source maps enabled for debugging
+  - Code splitting with vendor chunk (React/React-DOM)
+  - Lucide-react excluded from optimizeDeps for compatibility
 - Docker deployment uses Nginx to serve static files on port 3800
 - Host Nginx reverse proxy configuration available in `nginx-host.conf`
-- PWA manifest and service worker for mobile app installation
\ No newline at end of file
+- PWA manifest (`public/manifest.json`) and service worker (`public/sw.js`) for mobile app installation
+
+### CI/CD Pipeline
+
+**Automated Builds**:
+- Gitea Actions workflow at `.gitea/workflows/build-deploy.yml`
+- Triggers on push to `main` branch
+- Builds multi-stage Docker image (Node build → Nginx serve)
+- Pushes to Gitea container registry at `code.puffinoffset.com/matt/puffin-app`
+
+**Image Tagging Strategy**:
+- `latest`: Always points to most recent main branch build
+- `main-<commit-sha>`: Specific commit version for rollbacks
+
+**Container Registry**:
+- Gitea's built-in Docker registry
+- Authentication via Gitea credentials
+- Registry URL: `code.puffinoffset.com`
+
+**Deployment**:
+- Manual deployment via Portainer
+- Use `docker-compose.portainer.yml` for production stack configuration
+- Environment variables mounted via `.env` file volume
+- Detailed deployment instructions in `DEPLOYMENT.md`
+
+**Workflow Optimization**:
+- Docker buildx for multi-platform support
+- Layer caching to speed up builds
+- Separate build cache stored in registry
+
+### Key Implementation Details
+
+**Routing without React Router**: App uses state-based routing via `currentPage` state and `window.history.pushState()`. The `/mobile-app` route is detected by checking `window.location.pathname` and renders only `MobileCalculator` without the standard layout.
+
+**Sample Vessel Data**: A hardcoded `sampleVessel` object is used as default vessel data in `App.tsx` (lines 17-24) since AIS client currently returns mock data.
+
+**Analytics Integration**: `utils/analytics.ts` tracks page views via Google Analytics. Called in `App.tsx` useEffect when route changes.
+
+**Currency Support**: `utils/currencies.ts` provides multi-currency conversion. Calculator components support USD, EUR, GBP selection.
+
+**Error Handling**: `ErrorBoundary.tsx` component wraps the app to catch React rendering errors gracefully.
\ No newline at end of file
diff --git a/DEPLOYMENT.md b/DEPLOYMENT.md
new file mode 100644
index 0000000..8e23abf
--- /dev/null
+++ b/DEPLOYMENT.md
@@ -0,0 +1,243 @@
+# Puffin Offset - Deployment Guide
+
+This guide covers deploying the Puffin Offset application using Gitea Actions for automated builds and Portainer for container orchestration.
+
+## Architecture Overview
+
+```
+Push to main → Gitea Actions → Build Docker Image → Push to Registry → Manual Deploy via Portainer
+```
+
+## CI/CD Pipeline
+
+### Automated Build Process
+
+When code is pushed to the `main` branch:
+
+1. **Gitea Actions triggers** automatically
+2. **Docker image is built** using the multi-stage Dockerfile
+3. **Image is pushed** to Gitea's container registry with two tags:
+   - `latest` - Always points to the most recent build
+   - `main-<commit-sha>` - Specific commit for rollback capability
+
+### Registry Location
+
+Images are stored at:
+```
+code.puffinoffset.com/matt/puffin-app:latest
+code.puffinoffset.com/matt/puffin-app:main-<sha>
+```
+
+## Portainer Deployment
+
+### Prerequisites
+
+1. **Portainer installed and accessible**
+2. **Gitea registry credentials configured in Portainer**
+3. **Environment variables prepared** (see below)
+
+### Step 1: Configure Gitea Registry in Portainer
+
+1. Navigate to **Portainer → Registries**
+2. Click **"Add registry"**
+3. Configure:
+   - **Name**: `Gitea - code.puffinoffset.com`
+   - **Registry URL**: `code.puffinoffset.com`
+   - **Authentication**: Enabled
+   - **Username**: Your Gitea username (e.g., `matt`)
+   - **Password**: Gitea access token or password
+4. Click **"Add registry"**
+
+### Step 2: Prepare Environment Variables
+
+Create a `.env` file on your server with the required variables:
+
+```bash
+# Example: /path/to/puffin-app/.env
+VITE_WREN_API_TOKEN=your-wren-api-token
+VITE_FORMSPREE_CONTACT_ID=your-formspree-contact-id
+VITE_FORMSPREE_OFFSET_ID=your-formspree-offset-id
+```
+
+**Note**: The env.sh script in the Docker image will inject these at runtime.
+
+### Step 3: Create Portainer Stack
+
+#### Option A: Using Portainer UI
+
+1. Navigate to **Portainer → Stacks**
+2. Click **"Add stack"**
+3. Configure:
+   - **Name**: `puffin-app`
+   - **Build method**: "Web editor"
+4. Paste the contents of `docker-compose.portainer.yml`
+5. In **Environment variables** section, add:
+   - Name: `ENV_FILE_PATH`
+   - Value: `/path/to/your/.env`
+6. Click **"Deploy the stack"**
+
+#### Option B: Using Git Repository
+
+1. Navigate to **Portainer → Stacks**
+2. Click **"Add stack"**
+3. Configure:
+   - **Name**: `puffin-app`
+   - **Build method**: "Repository"
+   - **Repository URL**: `https://code.puffinoffset.com/matt/puffin-app.git`
+   - **Repository reference**: `refs/heads/main`
+   - **Compose path**: `docker-compose.portainer.yml`
+   - **Authentication**: Configure with your Gitea credentials
+4. Click **"Deploy the stack"**
+
+### Step 4: Verify Deployment
+
+1. Check that the container is running:
+   - Navigate to **Portainer → Containers**
+   - Look for `puffin-app-web-1` or similar
+   - Status should be "running"
+
+2. Test the application:
+   - Access: `http://your-server:3800`
+   - Or via your Nginx reverse proxy configuration
+
+3. Check logs if needed:
+   - Click on the container
+   - Select **"Logs"** tab
+
+## Updating to New Versions
+
+### Method 1: Using Portainer UI (Recommended)
+
+1. Navigate to **Portainer → Stacks**
+2. Click on **puffin-app** stack
+3. Click **"Update the stack"**
+4. Enable **"Pull latest image version"**
+5. Enable **"Re-pull image and redeploy"**
+6. Click **"Update"**
+
+Portainer will:
+- Pull the latest image from Gitea registry
+- Recreate the container with the new image
+- Maintain your environment variables and configuration
+
+### Method 2: Pull Specific Version
+
+To rollback or deploy a specific commit:
+
+1. Edit the stack in Portainer
+2. Change the image tag from `latest` to `main-<commit-sha>`
+   ```yaml
+   image: code.puffinoffset.com/matt/puffin-app:main-abc1234
+   ```
+3. Update the stack
+
+## Monitoring Build Status
+
+### Check Gitea Actions
+
+1. Go to your Gitea repository: `https://code.puffinoffset.com/matt/puffin-app`
+2. Navigate to **"Actions"** tab
+3. View recent workflow runs
+4. Click on a run to see detailed logs
+
+### Verify Image in Registry
+
+1. In Gitea, navigate to **"Packages"** or **"Registry"**
+2. Look for `puffin-app` images
+3. Verify tags: `latest` and `main-<sha>` tags should be present
+
+## Troubleshooting
+
+### Build Failed in Gitea Actions
+
+**Check the workflow logs:**
+1. Go to Gitea → puffin-app → Actions
+2. Click on the failed run
+3. Review error messages
+
+**Common issues:**
+- Registry authentication failed: Check secrets.GITHUB_TOKEN is available
+- Build errors: Review Dockerfile and build logs
+- Network issues: Check runner connectivity
+
+### Image Pull Failed in Portainer
+
+**Error:** `unauthorized: authentication required`
+
+**Solution:**
+1. Verify registry is configured in Portainer (Step 1)
+2. Check credentials are correct
+3. Ensure registry URL is `code.puffinoffset.com` (no `https://`)
+
+### Container Won't Start
+
+**Check environment variables:**
+1. Verify `.env` file exists on the host
+2. Ensure volume mount path is correct in docker-compose.portainer.yml
+3. Check container logs for missing env var errors
+
+**Check port conflicts:**
+1. Ensure port 3800 is not already in use
+2. Run `netstat -tuln | grep 3800` on the host
+
+### Application Not Accessible
+
+**Verify container is running:**
+```bash
+docker ps | grep puffin-app
+```
+
+**Check nginx reverse proxy:**
+- Review host Nginx configuration (`nginx-host.conf`)
+- Ensure proxy_pass points to correct container port
+- Test direct access: `http://server-ip:3800`
+
+**Check firewall:**
+```bash
+# Example for ufw
+sudo ufw status
+sudo ufw allow 3800/tcp
+```
+
+## Environment Variables Reference
+
+| Variable | Description | Required |
+|----------|-------------|----------|
+| `VITE_WREN_API_TOKEN` | Wren Climate API authentication token | Yes |
+| `VITE_FORMSPREE_CONTACT_ID` | Formspree contact form endpoint ID | Yes |
+| `VITE_FORMSPREE_OFFSET_ID` | Formspree offset order form endpoint ID | Yes |
+| `NODE_ENV` | Node environment (set to `production`) | Auto-set |
+
+## Rollback Procedure
+
+To rollback to a previous version:
+
+1. Find the commit SHA of the working version
+2. In Portainer, edit the stack
+3. Change image tag to `main-<previous-sha>`
+4. Update the stack
+
+Example:
+```yaml
+# Before (current broken version)
+image: code.puffinoffset.com/matt/puffin-app:latest
+
+# After (rollback to specific commit)
+image: code.puffinoffset.com/matt/puffin-app:main-ab0dbbd
+```
+
+## Security Best Practices
+
+1. **Never commit `.env` file to git** (already in .gitignore)
+2. **Use Gitea access tokens** instead of passwords for registry auth
+3. **Restrict registry access** to necessary users
+4. **Review Gitea Actions logs** for sensitive data exposure
+5. **Keep base images updated** (node:20-alpine, nginx:alpine)
+
+## Next Steps
+
+- Set up monitoring/alerting for failed builds
+- Configure automatic backups of `.env` file
+- Implement health checks in docker-compose
+- Set up SSL certificates via Let's Encrypt
+- Configure log aggregation for production debugging
diff --git a/docker-compose.portainer.yml b/docker-compose.portainer.yml
new file mode 100644
index 0000000..0100414
--- /dev/null
+++ b/docker-compose.portainer.yml
@@ -0,0 +1,29 @@
+version: '3.8'
+
+services:
+  web:
+    image: code.puffinoffset.com/matt/puffin-app:latest
+    ports:
+      - "3800:3800"
+    environment:
+      - NODE_ENV=production
+    restart: unless-stopped
+    volumes:
+      # Mount .env file for runtime environment variable injection
+      - ./.env:/usr/share/nginx/html/.env:ro
+    # Optional: override nginx config if needed
+    # - ./nginx.conf:/etc/nginx/conf.d/default.conf:ro
+
+# Production deployment notes:
+# 1. Ensure .env file exists on the host with required variables:
+#    - VITE_WREN_API_TOKEN
+#    - VITE_FORMSPREE_CONTACT_ID
+#    - VITE_FORMSPREE_OFFSET_ID
+#
+# 2. Configure Gitea registry authentication in Portainer before deploying
+#
+# 3. To update to new image:
+#    - Navigate to stack in Portainer
+#    - Click "Update the stack"
+#    - Enable "Pull latest image version"
+#    - Click "Update"