docs: update overview.puml color scheme to match state diagram and add construction warnings to readme

Author: jknoxdev

README.md

@@ -8,16 +8,26 @@
 [![Platform](https://img.shields.io/badge/platform-nRF52840-orange?style=flat-square)](https://www.nordicsemi.com/Products/nRF52840)
 [![RTOS](https://img.shields.io/badge/RTOS-Zephyr%20%2F%20NCS-7EC8E3?style=flat-square)](https://developer.nordicsemi.com)
 [![Status](https://img.shields.io/badge/status-WIP-red?style=flat-square)](#roadmap)
+![Last Commit](https://img.shields.io/github/last-commit/jknoxdev/lima-node)
 
-
+> ⚠️ **Work in Progress**
+>
+> L.I.M.A Node is under active development. The current phase focuses on
+> stabilizing the firmware state machine before integrating sensors,
+> cryptographic packet signing, and radio transport.
 ---
 
+
+
 ## What is LIMA?
 
 LIMA nodes are small, battery-powered sensors that detect physical integrity events — door opens, enclosure breaches, vehicle towing, cabinet punctures — and deliver cryptographically signed alerts to a local gateway, which routes them to operators via push notification, SIEM, or cloud audit trail.
 
 The system is designed to be **air-gapped first**. No cloud dependency for core operation. No persistent BLE connections. No trusted local network required. Just a node, a gateway, and a signed audit trail that survives internet outages.
 
+## System Overview
+
+
 **Two independent threat models, one pipeline:**
 
 | Trigger | Use Case | Sensor |
@@ -101,7 +111,7 @@ Each fires independently. An attacker must defeat both sensors simultaneously to
 
 ## Getting Started
 
-See [`docs/FLASHING.md`](docs/build/FLASHING.md) for the complete build and flash guide.
+See [`docs/build/FLASHING.md`](docs/build/FLASHING.md) for the complete build and flash guide.
 
 ```bash
 # 1. Initialize workspace

docs/architecture/overview.puml

@@ -0,0 +1,37 @@
+@startuml overview
+!pragma layout smetana
+
+skinparam {
+    BackgroundColor #1a1a2e
+    ArrowColor #7EC8E3
+    ArrowFontColor #CCCCCC
+    ArrowFontSize 10
+    DefaultFontName Arial
+    DefaultFontColor #E0E0E0
+    DefaultFontSize 11
+    StateBorderColor #4A90D9
+    StateBorderThickness 2
+    StateBackgroundColor #0f3460
+    StateFontColor #FFFFFF
+    StateFontSize 12
+}
+
+title L.I.M.A Node — System Overview
+
+
+state "Sensors" as sensors
+state "Event Detection" as detect
+state "FSM\n(State Machine)" as fsm
+state "Signed Event Record" as packet
+state "BLE Transport" as ble
+state "Gateway" as gw
+state "MQTT / Storage / Alerts" as backend
+
+sensors --> detect
+detect --> fsm
+fsm --> packet
+packet --> ble
+ble --> gw
+gw --> backend
+
+@enduml