Improve Theme Color Schemes and Fix Pause/Resume Button Functionality

I’ve been exploring the Pong game project and really appreciate the work done so far! However, I noticed a few areas that could use improvement to enhance the overall user experience:

Theme Color Schemes:
The existing themes have minimal visual difference, which reduces the impact and personalization options for users. Enhancing the color contrasts and adding more distinct palettes would make theme switching more noticeable and enjoyable.

Pause/Resume Button:
The Pause and Resume button currently exhibits inconsistent behavior — sometimes it doesn’t pause or resume the game properly, which affects gameplay control. Fixing this will improve usability and provide smoother game management.

I would like to contribute by refining the CSS for better theme differentiation and fixing the Pause/Resume button logic.

Thank you for considering this!
@Akki-jaiswal