Solved the problem thanks to Francis Daly who pointed me to the right direction:
https://forum.vuejs.org/t/vue-with-nginx/26843/3

// vue.config.js
module.exports = {
// options...
publicPath: '',
devServer: {
host: '0.0.0.0',
port: 8080,
public: 'ggc.world'
},
}

Now it works fine: https://drive.google.com/open?id=1PUctgdYLoVmJRvYyG040BFNGOev2yhRX

Besides to Francis, whose contribution was resolutive, I thank J.S. and Reinis for their kind help.