Bug: max-w uses --spacing instead of --container #17776

What version of Tailwind CSS are you using?
v4.1.4

What build tool (or framework if it abstracts the build tool) are you using?
TailwindPlay

What version of Node.js are you using?
N/A

What browser are you using?
Any

What operating system are you using?
Any

Reproduction URL
https://play.tailwindcss.com/cA87EpnMu8

@theme {
  --spacing-xs: calc(var(--spacing) * 1);
}

Describe your issue
The max-w-* utility classes currently use the --spacing-* variables for their width values. However, according to the official Tailwind documentation on max-width, these utilities are supposed to use the --container-* variables.