Describe the bug

Due to #9207 and the button component for Base UI being use client, you can no longer import buttonVariants and do className={buttonVariants()} on a <Link /> for example.

You end up getting

Attempted to call buttonVariants() from the server but buttonVariants is on the client. It's not possible to invoke a client function from the server, it can only be rendered as a Component or passed to props of a Client Component.

Affected component/components

Button

How to reproduce

1. Install the button component from Base UI
2. Import buttonVariants from that file
3. Add className={buttonVariants()} to something like next/link
4. Render that component onto a page and run it in localhost

Codesandbox/StackBlitz link

No response

Logs

System Info

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 25.2.0: Tue Nov 18 21:09:40 PST 2025; root:xnu-12377.61.12~1/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 10
Binaries:
  Node: 24.12.0
  npm: 11.6.2
  Yarn: 1.22.22
  pnpm: 10.20.0
Relevant Packages:
  next: 16.1.4
  eslint-config-next: N/A
  react: 19.2.3
  react-dom: 19.2.3
  typescript: 5.9.3
Next.js Config:
  output: N/A

Before submitting

• I've made research efforts and searched the documentation
• I've searched for existing issues