Most of the relevant source code is in the /ts/ (typescript) directory. Start with index.tsx and trace from there.
Css is in the /css directory
Follow the code from index.html to ts/index.tsx and beyond. Basically source code is in the ts/ directory.
create local environment and local vm:
clone this repo to dev.budgetpedia.ca
from inside the vm, cd /var/www/dev.budgetpedia.ca
run npm install to install all necessary node modules