Memory game made with Vue and Typescript

What are you most proud of, and what would you do differently next time?

1. Testing: I've covered core game logic and some components logic with unit tests.
2. Decoupling game logic from presentation layer for easy testing and refactoring.

What challenges did you encounter, and how did you overcome them?

1. Responsiveness always takes me considerable amount of time, and there are some inconsistencies with the design left. I'm planning to tweak them in the future.
2. I spend some time deciding on how to structure core logic module, and in the end I chose object oriented approach with inheritance.

What specific areas of your project would you like help with?

1. Code structure and OOP approach in src/core
2. Any tips on responsiveness, especially css units and breakpoints.
3. Vue code structure. I don't know if placing styling and logic in App.vue is acceptable, or should I perhaps move styling and logic somewhere else.
4. Overall tips on organizing code.
5. Any feedback is highly appreciated.