Of course, the current version of this website was also something I made. :)
In the beginning I set a couple of rules: I wanted to learn CSS Grid, and I wanted to see if I could put together something interesting without a single line of Javascript anywhere, using CSS and HTML only, a decision I mostly relish but sometimes regret when I go to update this page with new content :)
The site I started with leveraged CSS Grid quite heavily, but I eventually scrapped in favor of this "less Mondrian" design. Cross browser parallax is actually pretty hard. CSS has a long way to go, still! Or the companies that build some of our browsers do, anyway.
In any case, I am not sure I would attempt such a feat again, especially as I am not a professional.
HTML and CSS. Code on Github