In order to fix the wired looking (small) font of Caprine for Windows you just have to change (add) the “zoomFactor” parameter in ressources\app\index.js right after webPreferences:
zoomFactor: 1.2,

Save the file and re-run the app. The font should be readable now.

More about Caprine – https://github.com/sindresorhus/caprine