Add smooth transitions and animations for a more "Fluent" and "Smooth" experience

[0Ky]

I wanted to open up a discussion around a potential enhancement to better align with two keywords prominently used in the README: "Fluent" and "Smooth". I find these terms used in the README a bit misleading given that the theme includes no transitions, animations, or visual effects. Everything happens instantly, which is great for performance, but not always for user experience.

Would the project be open to including subtle CSS transitions or animations to enhance the feeling of smoothness and fluency?

For example:

• Hover transitions on links, buttons, cards, etc.
• Fade-in animations on page load or section reveal
• Dark mode transitions instead of hard switches

Here are 3 examples of what fluent & smooth design looks like:
- Astro Nano by Mark Horn
- Astro Micro by Mark Horn
- Fuwari by Saica

I'm happy to mock up an example or open a PR and of course, I'm totally open to feedback, edits or changes to better align with the project's standards.

[adityatelange]

I'll remove these keywords in future.