You just freeze the minimal CSS file generated by Tailwind (it tree-shakes out any class selectors for tailwind classes you're not using) and remove all tailwind dependencies; you don't have to make any more changes to your code, you're just left with the classes you've already added to your markup, which still work. You can gradually change those out however you want, at your own pace.

Also, using tailwind doesn't mean you can't use CSS the way you're used to in addition to the tailwind classes, though it's possible you could end up with specificity issues if, for example, you've added a tag selector, like `div {...}` which is overridden by a class you've added to a specific div in your markup. This is pretty straightforward though, and if you've been using CSS for any amount of time you'll still find you have to think a lot less about specificity than going all-in on your own CSS