Type bench / the real sites

This is the whole change — not a sketch of it. Both sites declare their faces as four custom properties and re-export them through Tailwind's @theme inline, so overriding those four restyles every page, component and MDX doc. Paste this into src/app/globals.css and you have shipped it.

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A specimen sheet cannot tell you whether a face makes the hero grow a line or the nav wrap. This applies slot A, measures the real document, applies slot B, measures again, and restores what was on screen. Every number comes out of the running app.