./build.sh
This will place the minimised distribution of each website in the respective
src/main/resources/web/<site> direcotry.
In the IntelliJ runner, setup the Working Directory to <project-root>/cordapp/src/main/resources.
In a shell, cd web/<site> and run npm run watch. This will setup an automatic watch on the site's files and will rebuild on change.
Make sure you keep an eye on its output .. it's running ESLint!