Production build FOUC

I seem to be having an issue with production builds having FUOC on the initial render. My Production builds are launched via Vercel I am using the following: "@tanstack/react-query": "^5.66.0", "@tanstack/react-query-devtools": "^5.66.0", "@tanstack/react-router": "^1.125.6", "@tanstack/react-router-devtools": "^1.125.6", "@tanstack/react-router-with-query": "^1.125.6", "@tanstack/react-start": "^1.125.6", "@tailwindcss/postcss": "^4.1.11", "tailwindcss": "^4.1.11", Layout.tsx---- import appCss from '@/styles/app.css?url'; header... { rel: 'stylesheet', href: appCss },