Node Sass does not yet support your current environment: Windows 64-bit with Unsupported runtime (88)
Thanks to jonrsharpe. Worked for me: install / downgrade node.js to a stable version (LTS) like 14.15.0 install the compatible node-sass version via npm install node-sass@4.14.0; you can find the list here, or even install gulp-sasswith npm i gulp-sass –save-dev. direct link to list