Transfering from Codpen to VSC

Hi – new here but super stuck. I transferred my working code from codepen to VS code but I keep getting css errors!

Here’s the codepen:

i think css variables are defined inside of selectors or inside the :root

ref here
https://developer.mozilla.org/en-US/docs/Web/CSS/Using_CSS_custom_propertiesUsing CSS custom properties (variables) - CSS: Cascading Style Sheets | MDN