I suppose CSS Grid merits its own entry: I’m amazed at how simple it makes web-page layout; a combination of it with W3C responsive is perfect for what I need. I didn’t intend revamping existing pages, but the temptation was too much… Not that it makes sense to apply it to all pages, but definitely the ones that have more structure. Up till now, I’ve just let W3C do all the @media queries, but CSS Grid has made me want to do my own, and presentation exactly how I want it on various device-widths is a doddle (or thereabouts).