Bring up any said problem and I'll give you an efficient, robust, fast, simple and maintainable way to solve it in pure, native CSS (maybe even with further advantages!).
The time has come to embrace good ol' CSS again! Heheh.
- layout: flex and grid are great solutions, Tailwind just makes them extremely easy to use. Flex and grid are barely unusable without first defining at least 4 or 5 helper classes, more likely a dozen. Tailwind just provides them and makes them easy to use. I never could remember the flex properties, I learned the Tailwind classes I needed in like half a day of practice
- mobile first design: Tailwind strongly encourages mobile first design if you want to do responsive design. It scared me at first because media queries are hard to manipulate in CSS. I've never made a responsive design page faster than with Tailwind, it's insane how easy it is
- dark mode: as simple as `dark:xxx`. The default and dark properties being close together is awesome. As with responsive design, Tailwind prefixes make it so easy to do what's painful in plain CSS
- defaults: having sane, overridable defaults for everything (sizes, colors, whatever) makes the code infinitely more consistent. You barely even need to think about real values, just how it looks, and you have less risk of defining slightly different classes for no reason
- no cascading: CSS cascading makes it hard to reason about styles, and easy to break unrelated components by mistake. It's solved with CSS modules (or even with BEM), but Tailwind just eliminates the problem
CSS has the solutions, it just doesn't make them easy to use.
2. You barely need media queries anymore for responsive design. Auto-adapting flex or grid containers and the use of clamp() reduced 90% of my media query usage. I usually use like 1 to 4 media queries in project (for master layout and responsive nav, for example). And there's a nice side effect to this type of intrinsic design : layout and type is way easier to optimize for every viewport! Mobile first design is really easy to approach in this way.
3. You can apply a dark mode by only switching a theme file with design tokens inside. Way lighter, way easier to read, does not clutter your codebase.
4. As a corollary to the previous point, the defaults you are talking about can be CSS custom properties defined in a theme file as I think, Tailwind 4 will do. You could then use the exact same defaults in native CSS.
5. Simple rules about CSS usage, enforced by Stylelint for example, can prevent the vast majority (and maybe all!) of the cascading problems you mention. Here are some rules and a Stylelint config I posted in a reply below: https://ecss.info. I've got a good track record with teamwork and this config.
CSS solutions may be really easy to use when approached properly. I'm happy to follow up with examples and/or reply to subsequent questions and thoughts!