Description

This Pull Request introduces a comprehensive modernization of the application's user interface, bringing a more elegant and user-friendly experience to run and read the JavaScript code examples.

Here is a summary of the improvements:

Key Features

• Modern aesthetics: Redesigned index.html and index.css adopting a clean, modern, and responsive layout.
• Built-in Code Viewer: Replaced the friction of asking users to open the browser's Developer Console (F12) to see results. There is now a dedicated, styled code window right on the page to display the JavaScript snippets and execution outputs directly.
• Internationalization (i18n): Added a language toggle mechanism. The interface now supports both English (en) and Portuguese (pt-br), making the project accessible to a broader audience without duplicating HTML files.
• Refactoring: Cleaned up app.js and util_web.js to support the new UI interactions seamlessly without breaking the original algorithms.

Screenshots

Why?

The "Classic Computer Science Problems" is a fantastic resource. However, requiring users to rely on the Developer Console makes it harder for beginners to quickly explore the algorithms. This visual revamp improves the project's presentation, making it feel like a polished web app.

Please let me know if any adjustments are needed, I'd be happy to iterate on this!