updating README

README.md

 
 ## Application structure
 
-The ExPub Compendium is a Python application using the [Flask](https://flask.palletsprojects.com/en/2.2.x/) framework to render as a website and to provide functions around user authentication and login as well as retrieving data from the underlying database. The database is a MariaDB SQL database with a basic structure of Resources, Relationships, and Users. Resources are divided into tools, practices, and books and the table contains fields for these various types of resources. Relationships defines the links between resources using the resource ID in the Resource table: these are rendered on the site as connections between, say, a tool and a practice. Users contains the site's users with basic details like email address and hashed password. 
+The ExPub Compendium is a Python application using the [Flask](https://flask.palletsprojects.com/en/2.2.x/) framework to render as a website and to provide functions around user authentication and login as well as retrieving data from the underlying database. The Flask framework uses a few HTML template pages to render different pages efficiently based on routes defined in Python files. These template pages use a fairly basic [Bootstrap 5](https://getbootstrap.com/) grid design which allows for responsive design using in-built CSS and HTML elements. 
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+The database is a MariaDB SQL database with a basic structure of Resources, Relationships, and Users. Resources are divided into tools, practices, and books and the table contains fields for these various types of resources. Relationships defines the links between resources using the resource ID in the Resource table: these are rendered on the site as connections between, say, a tool and a practice. Users contains the site's users with basic details like email address and hashed password. This simple structure provides flexibility for displaying resources with filters and to illustrate the connections between various resources. 
 
 ## Database functions