How to fix "unknown @ rule errors" on Zed when using Tailwind v4

There is a simple trick to not show the unknown @ rule errors warnings on CSS files using @apply or other @ properties.

Sunday, December 21, 2025 at 9:06AM1 min read

I switched back to Zed from Antigravity. It was fun when it lasted until I reflected on 2025 on the whole only to realize most of my programming interaction has been with an agent (Cursor specifically), rather than me breaking my head and learning new things.

The moment I moved back, I hit up on this annoying warning on my CSS files which shows "unknown @ rule errors" when you use Tailwind v4 for your projects on Zed.

The trick is simple. Since Tailwind CSS Language Server is already included in your Zed editor, all you have to do it to make Tailwind LS as your default language server for CSS files.

To do this, open your Zed settings and search for "language server". Then, add the following configuration:

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"languages": {
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    "CSS": {
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      "language_servers": ["tailwindcss-language-server"],
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    },
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  },

That's it. Now you can use Tailwind v4 without any warnings on Zed.

Ref:

Solution on GitHub Issue.