TYPOGRAPHY_ENGINE_RFC Phase 1. Additive on TypographyPrimitiveSet, behind the frozen
token contract (--font-size-X keeps its name; only the value formula changes, like
color --scale-* hex -> oklch()).
- type-scale.ts (pure, isomorphic, no canvas): the Utopia clamp() formula. fluidClamp /
resolveTypeSize / isFluidSize. rem-based (a11y: scales with browser font-zoom).
- config-types: TextMetric.size accepts `string | FluidSize` ({min,max,minVw?,maxVw?}).
Plain length strings still valid -> backward-compatible.
- render-css appendTypographyDeclarations: emits calc(resolveTypeSize(size) * --scaling)
-> a fixed rem or a fluid clamp; the --scaling axis composes on top.
- config.ts: validateSizeValue accepts a FluidSize (validates min/max/minVw/maxVw) so
the base config validates (was the cascade root — FluidSize objects failed the
string-only CSS-value check).
- typography.ts: sizes in rem; headings (lg/xl/xxl/xxxl) fluid (min @480px -> max
@1280px, max = previous fixed px so desktop is unchanged); body (md) fixed. hero/h1/h2
drop the manual { base, md } responsive sizes — the clamp covers the viewport.
- generated/base.css regenerated. type-scale.test.ts (6 tests). 2 config-test assertions
updated to the new rem/clamp values.
Verified in browser: --font-size-xxxl 40px @480 -> 80px @1280; xxl 32->48; lg 18->20;
md 16 fixed. check 0 errors; eidos suite green (3 pre-existing words failures only).
canvas-text/<SText> unaffected (reads getComputedStyle real font, measures the clamp).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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