I don't understand what people mean when they say things like CSS has gotten more complex. It's not like anyone is realistically expected to commit the entire spec to memory.
Documentation is plentiful when a person needs to use an unfamiliar feature, so it's not like it is even necessary to keep everything you use at the top of your mind. And just like anything else, if you use is often, you'll naturally learn it.
Plus, things like flex and grid have made having to remember a ton of old hacks unnecessary, so it has actually gotten markedly easier to use.
Documentation is plentiful when a person needs to use an unfamiliar feature, so it's not like it is even necessary to keep everything you use at the top of your mind. And just like anything else, if you use is often, you'll naturally learn it.
Plus, things like flex and grid have made having to remember a ton of old hacks unnecessary, so it has actually gotten markedly easier to use.