removing node sass

[CheetoMao]

• removed node sass in favor of just sass
• reworked media queries so that syntax makes sense for dart sass
• made sure all math is wrapped in calc
• updated hero, cta, and doc site sidebar gradient
• updated font sizes for doc site

[nschello]

This pr is currently missing some fixes that found were still necessary when updating the maths transitions in dart sass.

Work most likely to be continued in the https://github.com/revelrylabs/harmonium/tree/chore/node-16 as it encompasses a node16 upgrade as well

[nschello]

closing in favor of https://github.com/revelrylabs/harmonium/pull/663