Tailwind replaces having to come up with a new semantic class name every time you need to style an element only to realize the actual semantics you picked were completely wrong.
Tailwind is basically a cleaner way to do everything as inline styles.
I'd say that's underselling it. For one thing it keeps you within a design system. By default you're given spacing that works in increments of 0.25rem, a handful of colors, etc to work with (which can be replaced/extended) so you have to go out of your way to break the design system that's in place.
Also inline styles don't allow for hover, focus, @media, etc. Which were always a pain in the ass with normal CSS anyway. Using Tailwind was the first time I didn't find writing a responsive UI to be a giant hassle. You just design for mobile and then for anything that needs to change on bigger screens you put a sm: or lg: or whatever breakpoint style and you're done.
Tailwind doesn't make you copy and paste, it moves the reuse of styles out of CSS which sucks at managing reuse into whatever HTML building system which likely has some concept of reusable views.
Then they make `.box` and include it as a mixin. Like CSS developers have done for a decade (and which tailwind itself does using PostCSS)
> Tailwind doesn't make you copy and paste
Yes it does. Moving all styles into individual elements without reuse is copy and paste.
Tailwind all but assumes you will be using something that allows you to extract HTML into components, be that something like React or Vue, or classic partials in a server-side templating language like Twig. You reuse the entire component, rather than just the CSS, which IMO is far better aligned with how apps are actually built.
So no, using Tailwind classes is no more copy pasting than typing CSS in full into a separate stylesheet is copy pasting.
Login box and messages are separate components, but they share padding metrics, border styles, a palette, etc.
Have you used tailwind before?
My argument is that using the “mr-1 pl-2” utilities on both a login box and a message would be no more copy pasting than creating a stylesheet with “.login-box { margin-right: 0.25rem; padding-left: 0.5rem; }” and “.message { margin-right: 0.25rem; padding-left: 0.5rem; }”.
And if you’re suggesting that you would create a single CSS class with those properties to apply to both the login box and the message, then it’s my opinion that that is a broken abstraction that falls apart as soon as your designer asks if you can make the spacing in the login box a little looser.