MacBook. Probably an M2 Air.
Obviously you should talk to your wife yada yada like everyone else said, but my opinion is that a MacBook would be best. Best battery life, screens etc plus the ecosystem stuff you mentioned with her iPhone.
It provides a massive set of CSS classes which allows you to do styling inside HTML instead of manually in CSS. It provides the benefits of consistency and reduces the need to name things which can be a big time sink. It only includes the classes that you use in the final build.
It does have the potential to significantly bloat HTML when many classes are needed for a given element though, and directly opposes the original intent that HTML defines only content while CSS defines styling.
I have an M1 Pro 16 and love it, but its already huge $3750 AUD price tag has ballooned to $4250 for the M3 Pro 16 whose only difference is the chip. I love my MacBook but unless Apple returns to earth with their pricing and/or makes the machines worth that much by providing more than the barest essential specs at those prices, I will be buying something else when this MacBook is done.