backend_design.txt

The backend will be a Python Flask server with the following components:

1. Main Flask app:
   - Import necessary libraries (Flask, difflib)
   - Create Flask app instance

2. Route: "/"
   - Serve the main HTML page

3. Route: "/compare" (POST method)
   - Receive two texts from the frontend
   - Use difflib to compare the texts and generate HTML diff
   - Return the HTML diff to the frontend

4. Helper function: generate_diff(text1, text2)
   - Use difflib.HtmlDiff().make_file() to create an HTML diff
   - Customize the output to make it more visually appealing

5. Run the Flask app

The server will use the difflib library to generate a colorized HTML diff between the two input texts. This diff will highlight additions, deletions, and changes between the two versions.