Love the Rebuilding Rails concept! I'm doing a very similar thing in Ruby, focused more on "web application development from first principles" (https://theodorekimble.ck.page/e0bb43b156). I know I better absorb concepts if I can trace them back to a more fundamental "truth".
Curious to hear if anyone else has found success with Rebuilding Rails, and what they found most helpful.
If you want to do the same thing (build up from 1st principles) with CSS, I ravingly endorse Axiomatic CSS as defined and implemented in https://every-layout.dev
Disclaimers: no affiliation, just a very satisfied customer. IME the free content alone is illuminating, and having paid $100 to access to the full "book" incl all the layouts' implementation it was a bargain.
Curious to hear if anyone else has found success with Rebuilding Rails, and what they found most helpful.