[docs-infra] Hide Tailwind variables from the dev tools when not used

[danilo-leal]

Summary

This issue is a reference to this comment: #37319 (comment)

Tailwind is used mainly within the Base UI docs, where we provide a way for readers to toggle the styling engine the demos use to style components. There might be other places, but in most other pages, Tailwind is not used, and therefore, we could not load it somehow so it doesn't clutter up the dev tools and boosts a bit of performance.

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