Install

npm i

Run

./node_modules/gulp/bin/gulp.js

or if you have Gulp installed globally

gulp

Problem

susy-breakpoint() mixin wipes variables after it has been called. Variables like $mobile: $mobile: 640px; are left untouched, query-like variables $tablet: 641px 1024px are being erased.

See @debug messages on building src/app.scss and resulting css in build/app.css.