Error: Node Sass does not yet support your current environment: Linux 64-bit with Unsupported runtime (88)

node-sass does not support Node 15 (runtime **) currently. It will come with when v5 when it is published to NPM. You can subscribe to the tracking issue here https://github.com/sass/node-sass/issues/2965 node-sass 4.x will not receive support for Node 15 https://github.com/sass/node-sass#node-version-support-policy, so you may want to downgrade your Node version to 14 currently