Custom Component State Not Working with Modifiers

[PruthviPraj00]

What version of Tailwind CSS are you using?

v4.0.13

Reproduction URL

https://play.tailwindcss.com/V9PpCvsjHl

Describe your issue

I'm experiencing an issue where component states, like an active state on a button, aren't working as expected when using the modifiers. In the example I provided (link above), I've created a simple button component with a .btn-active state. However, when I try to apply styles using the modifier, they don't take effect.

You can see the problem in the provided playground link, and I’ve also attached a screenshot for reference.

[wongjn]

You'd need to use @utility so that Tailwind knows about the class name. This is so that Tailwind could then add variants to it. Also, you'd want to place the .btn in a @layer so as not to take precedence over utility class names.

https://play.tailwindcss.com/8729GQoTF3?file=css

[PruthviPraj00]

Hello @wongjn,

Thank you for your help. But this will be my structure.

@layer utilities {
  .btn {
    @apply h-12 rounded-md bg-amber-600 px-4 text-white;
  }
  @utility btn-active {
    &.btn {
      background-color: var(--color-black);
    }
  }
}

But this throw error

`@utility` cannot be nested.

[wongjn]

Unnested the @utility outside the @layer.

[PruthviPraj00]

I would have done that if I could

[wongjn]

I don't believe anything should stop you from doing so.

[PruthviPraj00]

For my button.css file, when importing it, I use this syntax:

@import "@/styles/components/button.css" layer(components);

to specify that it belongs to the components layer.

I'm using a 3rd party UI kit

[wongjn]

You add the components layer inside the @utility like:

@utility btn-active {
  @layer components {
    &.btn {
      background-color: var(--color-black);
    }
  }
}