I've learned that Tailwind is not really a framework so much as it is a philosophy. Most Tailwind classes are just single property wrappers. For example, "flex" is just "display: flex", "bg-dark-400" is just "background: $bg-dark-400", "text-white" is just "color: white"...that sort of thing. It is more of a rebuke of the CSS concept as a whole, as CSS is geared towards large but few classes, and Tailwind is smaller but many classes.
You can use Tailwind to build Bootstrap, like the OP link shows, but you can't do the opposite. I was surprised when browsing the Tailwind docs that they didn't have prebuilt navbar, form, or input classes, but now I realize that's actually the point. You have to build all of those yourself to fit the needs of your project. That's not to say that prebuilt components don't exist at all, just that they're not part of the Tailwind framework project - they exist under Tailwind UI, the commercial offshoot of Tailwind. It's pretty expensive as an indie developer, but I don't mind having to build my own components so it still works out for me.
You can use Tailwind to build Bootstrap, like the OP link shows, but you can't do the opposite. I was surprised when browsing the Tailwind docs that they didn't have prebuilt navbar, form, or input classes, but now I realize that's actually the point. You have to build all of those yourself to fit the needs of your project. That's not to say that prebuilt components don't exist at all, just that they're not part of the Tailwind framework project - they exist under Tailwind UI, the commercial offshoot of Tailwind. It's pretty expensive as an indie developer, but I don't mind having to build my own components so it still works out for me.
[1] https://tailwindui.com/