Let me check the CSS file to identify the custom property issue:

I found the issue! The CSS custom properties are defined using OKLCH color values with spaces that are being interpreted as invalid syntax. The problem is in how the OKLCH colors are written - they need to be in the correct format. Let me fix the globals.css file:

Fixed the CSS custom properties issue! The problem was with the malformed OKLCH color syntax using spaces. I've replaced all the CSS variables with valid hex color codes that are properly formatted and will work correctly with Tailwind CSS v4. The color scheme maintains the light and dark mode theming with proper contrast ratios for accessibility.

I can see two issues:

1. PostCSS configuration error - Tailwind CSS v4 moved the PostCSS plugin to @tailwindcss/postcss, so the config needs to be updated
2. "use client" directives missing - The React components using hooks need the "use client" directive for Next.js

Let me read the current files and fix them:

Now let me read the problematic component files to add the "use client" directives:

Now I'll fix all the issues:

Fixed the deployment errors! The issues were: 1) PostCSS config - Updated to use @tailwindcss/postcss for Tailwind CSS v4 compatibility, and 2) Missing "use client" directives - Added the directive to all components and hooks that use React hooks. The app should now build and deploy successfully to Vercel.