REST API countries with theme color switcher

1. What are the best practices for React app performance? Any documentation would be greatly appreciated.

2. Best practices regarding color theme switcher with MUI 5? I kind of used a work around for switching themes with a custom color palette, but I think there are easier ways to do this, I just don't know how.

3. Framer motion page transitions with React Router DOM v6.4. I've searched all over the place for anything that talks about how to create page transitions with both of them. I am using the data browsers (createBrowserRouter([]) with the loader functionality which is really great. However, I can't get to show page change animations since I can't practically use the useLocation() API hook. This was a nagging question, so if anyone has a solution. Please tell me.

Another really annoying question. The screenshot taken by FrontendMentor is taken at a zoom of 110% which disrupts the display a little bit. Any suggestions for t