There is a lot to CSS, SASS, etc, so alot of these notes will be in reference to further documentation you can find online.
Eventually very specific tools that we reuse will be noted either here or in a separate file.

One of the best resources you can go to for CSS is Kevin Powell on youtube:

https://www.youtube.com/channel/UCJZv4d5rbIKd4QHMPkcABCw

And also CSS-Tricks.com:

https://css-tricks.com

Specifically their CSS grid and flexbox tutorials:

https://css-tricks.com/snippets/css/a-guide-to-flexbox/

https://css-tricks.com/snippets/css/complete-guide-grid/

A great resource for figuring out use specific grid snippets can be found at gridbyexample.com:

https://gridbyexample.com/examples/