Docs: Add font conversion guide and link in user guide

FONT_CONVERSION.md

@@ -0,0 +1,37 @@
+# Font Conversion Guide
+
+To use custom fonts with the CrossPoint Reader, you must convert standard `.ttf` or `.otf` font files into the specific `.epdfont` binary format used by the compiled firmware.
+
+We use a Python script located at `lib/EpdFont/scripts/fontconvert.py`.
+
+## Requirements
+- Python 3
+- `freetype-py` library (`pip install freetype-py`)
+
+## Usage
+
+Run the script from the project root:
+
+```bash
+python3 lib/EpdFont/scripts/fontconvert.py --binary [Family-Style-Size] [Size] [PathToFont]
+```
+
+### Arguments
+1. `name`: The output filename (without extension). **Convention:** `Family-Style-Size` (e.g. `Bookerly-Regular-12`).
+2. `size`: The integer point size (e.g. `12`).
+3. `fontstack`: Path to the source font file (e.g. `fonts/Bookerly-Regular.ttf`).
+4. `--binary`: **REQUIRED**. Flags the script to output the `.epdfont` binary instead of a C header.
+
+### Example
+
+To convert `Bookerly-Regular.ttf` to a size 12 font:
+
+```bash
+python3 lib/EpdFont/scripts/fontconvert.py --binary Bookerly-Regular-12 12 fonts/Bookerly-Regular.ttf
+```
+
+This will generate `Bookerly-Regular-12.epdfont` in your current directory.
+
+## Installing on Device
+1. Rename the file if necessary to match the pattern: `Family-Style-Size.epdfont`.
+2. Copy the `.epdfont` file to the `/fonts` directory on your SD card.

USER_GUIDE.md

@@ -128,6 +128,12 @@ You can customize the sleep screen by placing custom images in specific location
 > - Use uncompressed BMP files with 24-bit color depth
 > - Use a resolution of 480x800 pixels to match the device's screen resolution.
 
+### 3.7 Custom Fonts
+
+You can load your own custom fonts onto the device by converting them to the required `.epdfont` format.
+
+See the **[Font Conversion Guide](FONT_CONVERSION.md)** for detailed instructions on how to use the conversion tool.
+
 ---
 
 ## 4. Reading Mode