I think aiming for pure HTML/CSS is good but doesn’t need to be the goal. There is a time and a place for JavaScript where it should be added thoughtfully and with minimal external dependencies.

Dell Optiplex’s are cheap and reliable

You can fit it on a £50 SSD, it’s not too big

Started using it a couple of weeks ago for our family and it really is great. Don’t necessarily follow it completely but it gives me some good inspiration!