REST Countries API with color theme switcher | Built with Sapper

Feedbacks are welcome!

This project is built with Sapper and I exported to the static site before deployed. All the subpages (the detail page for each country) are pre-cached by Sapper (which makes the speed of deployment super slow🤪).

I used the country code for each country's page instead of the country name to avoid validation error (some of the country names have invalid characters for url).

Also, It seems the HTML validator does not support image lazy loading 🤔