The fact that even the header parallax is janky on a laptop, not to mention a phone, doesn't instill the feeling that this is built sturdily. Looks aren't worth much if the page is laggy even with what's essentially static content. As another example, when ticking a box for the first time, there's a visible delay on state transitions. Toggling back and forth after that doesn't seem to be an issue. The crosses in badge removal look off, the corners are doubled as if there's two icons overlaid with a small position difference. The links in the site footer are practically unreadable with dark purple on a dark gray background.

Don't get me wrong, I don't mean to put your work down. Building a whole UI library from scratch is far from being a small feat and making it open source is definitely admirable. At the moment it feels like it could use some polish, though.