Update README.md

README.md

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-# ha-gammy-bridge
+# Home Assistant ↔ Gammy Bridge
 
-Windows Gammy (flux alternative) <-> HA control
+A simple Python MQTT bridge to control [Gammy](https://github.com/Fushko/gammy) (open-source adaptive screen brightness/color temperature tool for Windows) from Home Assistant.
+
+This lets you:
+- Trigger **Ember mode** (~1900K, dim) when your house goes into sleep mode.
+- Trigger **Movie mode** (6500K, bright) when watching movies.
+- Toggle **Auto mode** (Gammy’s circadian cycle) for normal use.
+- Send custom temperature + brightness commands from HA.
+- Query the current state back into Home Assistant.
+
+---
+
+## 🚀 Features
+- MQTT topic subscription: `pc/gammy/mode`
+- Supported commands:
+  - `ember [snap|fast|slow]`
+  - `movie [snap|fast|slow]`
+  - `auto [snap|fast|slow]`
+  - `custom <temperature> <brightness> [snap|fast|slow]`
+- Publishes current state to: `pc/gammy/state`
+- Fade support (`snap=0s`, `fast=1s`, `slow=30s`)
+
+---
+
+## 📂 Files
+- `gammy_mqtt.py` → Main script.
+- `requirements.txt` → Python dependencies.
+
+---
+
+## ⚡ Installation
+1. Install [Python](https://www.python.org/downloads/) (Windows).
+2. Install requirements:
+   ```bash
+   pip install -r requirements.txt