cheap
https://css-for-js.dev/
https://courses.joshwcomeau.com/css-for-js
https://courses.joshwcomeau.com/css-for-js/05-responsive-css/10-calc

2024
Staschuk - CSS Course for Beginners 0:00 of 1:27:34
    https://www.youtube.com/watch?v=WpridlBQmdk
    00d641600ea359f2f8aeda1d2f551303
2023
freeCodeCamp - CSS Tutorial – Full Course for Beginners 0:00 of 11:08:09
    https://www.youtube.com/watch?v=OXGznpKZ_sA