New interface, Better UX, Copy JSON feature

[housamz]

I created a new interface for the application to enhance the user experience.

The new Interface features:

1. Modern UI focusing on the file selector.
2. Enhancing the colours for better contrast.
3. Replacing CSS in base.css with the built-in classes in BassCSS.
4. Adding a button to copy the JSON output.
5. Adding scrolling buttons for the Download and the Copy actions.

Screenshots

Testing

1. Tested the new UI on computer screen.
2. Tested responsive on several devices.
3. Converting Linkedin files.
4. Tested the Download Button.
5. Tested the Copy button.