feat: compact UI with theme switcher (light/dark/mono)

- Redesign download cards to be significantly more compact
- Add CSS custom properties for theming
- Add theme switcher (Light, Dark, Mono) with localStorage persistence
- Update README with environment variable Docker deployment docs
- Update Docker Compose example to use environment: instead of volume mount

README.md

@@ -92,6 +92,25 @@ docker run -d \
 
 3. **Access the dashboard** at `http://your-server:3001`
 
+### Using Environment Variables (Alternative to .env file)
+
+All configuration can be passed directly as environment variables instead of mounting a `.env` file. This is the preferred approach for orchestrated deployments (Docker Compose, Kubernetes, Portainer, etc).
+
+```bash
+docker run -d \
+  --name sofarr \
+  --restart unless-stopped \
+  -p 3001:3001 \
+  -e EMBY_URL=http://emby.local:8096 \
+  -e EMBY_API_KEY=your-emby-api-key \
+  -e SONARR_INSTANCES='[{"name":"main","url":"http://sonarr:8989","apiKey":"your-key"}]' \
+  -e RADARR_INSTANCES='[{"name":"main","url":"http://radarr:7878","apiKey":"your-key"}]' \
+  -e SABNZBD_INSTANCES='[{"name":"main","url":"http://sabnzbd:8080","apiKey":"your-key"}]' \
+  -e QBITTORRENT_INSTANCES='[{"name":"main","url":"http://qbit:8080","username":"admin","password":"pass"}]' \
+  -e LOG_LEVEL=info \
+  docker.i3omb.com/sofarr:latest
+```
+
 ### Docker Compose
 
 ```yaml
@@ -103,10 +122,18 @@ services:
     restart: unless-stopped
     ports:
       - "3001:3001"
-    volumes:
-      - /opt/sofarr/.env:/app/.env
+    environment:
+      - EMBY_URL=http://emby:8096
+      - EMBY_API_KEY=your-emby-api-key
+      - SONARR_INSTANCES=[{"name":"main","url":"http://sonarr:8989","apiKey":"your-key"}]
+      - RADARR_INSTANCES=[{"name":"main","url":"http://radarr:7878","apiKey":"your-key"}]
+      - SABNZBD_INSTANCES=[{"name":"main","url":"http://sabnzbd:8080","apiKey":"your-key"}]
+      - QBITTORRENT_INSTANCES=[{"name":"main","url":"http://qbit:8080","username":"admin","password":"pass"}]
+      - LOG_LEVEL=info
 ```
 
+> **Tip:** You can also use a combination — mount a `.env` file for base config, and override specific values with `-e` flags. Environment variables always take precedence.
+
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