> The content is dated, using hacky techniques to work around deficiencies that no longer exist.
While I certainly agree that a lot has changed in the 4 years since Magic was authored, I think this statement is a little strong. I’d argue that chapters 1, 4, 5, and 6 hold up quite well and that 2 and 3 still contain useful information for newcomers to CSS—despite the absence of flex.
A chapter on flex is long overdue, no doubt, and chapters 2 and 3 should be written with this in mind. I’ll definitely get to it at some point, but I’d also be happy to collaborate with the community if anyone were interested in submitting a first draft [1].