The first one looks like a big part of the functionality is from the JavaScript file. It's crashing my iPhone so I'm having trouble digging into it too much. The second link, however, does seem to be done in pure css. Impressive! Thank you for the links. I stand corrected.
It is absolutely a limitation, because there are things you can express in other languages that you cannot in CSS.
But a limitation isn’t necessarily bad, and is often good. Finding the language of least power (ie it is just powerful enough to express the sorts of things you want, and no more) is very useful for safety and productivity, but in CSS’s case it seems like it’s no longer powerful enough to express all the things its users desire.
Its different and it a poor lang. The only people advocating for css only are privacy freaks. They're often the least return producing customers, hence ignored.
As far as I understand there are very good sides of CSS, as a declarative constraint language. More than being a poor language it looks like it is hard to use it for modern web development.
It has different functionalities.