Build error when using --color-*: initial theme reset in Tailwind CSS v4

[jeniabrook]

Description

When using Tailwind CSS v4's theme reset feature to override default color values with --color-*: initial;, the build fails with a TypeError.

Error

TypeError: Cannot use 'in' operator to search for '__CSS_VALUES__' in undefined

Environment

• Tailwind CSS: v4.1.17
• tailwindcss-motion: v1.1.1
• Build tool: @tailwindcss/cli

Reproduction

@import "tailwindcss";

@plugin "tailwindcss-motion";

@theme inline {
  --color-*: initial;  /* This line causes the error */
  --spacing-*: initial;
  --radius-*: initial;
  --text-*: initial;
  --font-weight-*: initial;
  --drop-shadow-*: initial;
  --breakpoint-*: initial;
  
  /* Custom theme values follow... */
}

Running @tailwindcss/cli with the above CSS produces the error.

Workaround

Commenting out only --color-*: initial; allows the build to succeed. All other namespace resets (--spacing-*, --radius-*, etc.) work fine.

@theme inline {
  /* --color-*: initial; */  /* Commenting this out fixes the issue */
  --spacing-*: initial;
  /* ... */
}

Expected Behavior

The plugin should work with Tailwind CSS v4's theme reset feature, or gracefully handle cases where default theme values are reset.