Bug Description

When setting a breakpoint using px in @theme, it does not work
correctly. But the same value in rem works fine.

Versions

• Tailwind CSS: v4.3.0
• @tailwindcss/postcss: v4.3.0
• Vite: v8.0.10
• React: v19.2.5

Code to Reproduce

@theme {
--breakpoint-lg: 992px; (does not work)
--breakpoint-lg: 62rem; (works perfectly)
}

Expected

992px and 62rem are the same width (992 / 16 = 62rem),
so both should behave identically.

Actual

px gets sorted before rem defaults in generated CSS,
so md: styles override lg: styles incorrectly
between 992px and 1024px.

Workaround

Use rem instead of px.