[jenil]

Summary

Migrates Chota's root font sizing so it no longer sets html { font-size: 62.5% }, removing the forced 1rem = 10px override that broke accessibility zoom and consumer root overrides. Every Chota-owned rem value is divided by 1.6 so rendered pixels are unchanged at a 16px consumer root.

Closes #137.

What changed

Source (35 rem tokens across 6 files):

• src/_base.css: --grid-maxWidth 120rem→75rem, --grid-gutter 2rem→1.25rem, --font-size 1.6rem→1rem; removed font-size: 62.5% from html; added a source comment explaining Chota does not set the root font-size; converted blockquote/hr/td,th/pre padding+margin.
• src/_card.css, src/_form.css, src/_nav.css, src/_tab.css, src/_tag.css: padding/margin/width/height/letter-spacing rem tokens converted.

Untouched (no rem): src/_dropdown.css, src/_grid.css (uses var(--grid-gutter)), src/_util.css, src/chota.css. All em/%/px/vh values unchanged — em-based typography (h1–h6, .tag.is-small/.is-large, .nav .brand, code/kbd) stays relative to the body font-size, which remains 16px.

Documentation:

• MIGRATION.md: new "Root Font-Size Migration" section (what/why/consumer impact/reference table/em-typography note).
• docs/index.html: updated the two Customizing code blocks and added a sentence stating Chota does not set the root font-size.

Build:

• dist/chota.css and dist/chota.min.css regenerated.
• baselines/size-baseline.json updated: gzip_bytes 3372→3373, gzip_budget_remaining_bytes 724→723, dist byte counts, plus a v1: migrate root font sizing without visual regression #137 rationale entry.

Consumer impact

• Did NOT override the root: no visual change. Body font-size still 16px (--font-size: 1rem at 16px root = 16px, same as old 1.6rem at 10px root = 16px).
• Set html { font-size: 62.5% }: Chota now renders at 0.625× its 16px-root size (proportional scaling, not a second baseline).
• Set a different root (e.g. 20px): Chota scales proportionally to that root.

Property	Before	After	Rendered px (16px root)
--grid-maxWidth	120rem	75rem	1200px (unchanged)
--grid-gutter	2rem	1.25rem	20px (unchanged)
--font-size	1.6rem	1rem	16px (unchanged)

Validation

• yarn build: PASS — stylelint clean, postcss, size-gate 3373 bytes (baseline: 3373, ceiling: 4096) → PASS: Within baseline and ceiling. (exit 0)
• yarn test:api: PASS — 5/5 on Chromium (exit 0). api-manifest.json records names only and the names are unchanged; manifest not edited.
• grep "62.5%" dist/chota.css: empty (override removed).
• grep "0.625rem" dist/chota.css: matches present (conversion applied).
• git diff --check: clean (no whitespace errors).

Size impact

Metric	Before	After	Δ
dist/chota.css bytes	18733	19039	+306
dist/chota.min.css bytes	14353	14419	+66
gzip bytes	3372	3373	+1

The +1 gzip byte comes from marginally longer decimal tokens (e.g. 0.625rem vs 1rem). Well within the 4096-byte ceiling; budget remaining: 723 bytes.

Scope

• Base: v1 @ 980c1f4
• Branch: work/137-root-font
• Commit: f2c1102
• 11 files changed, 99 insertions(+), 67 deletions(-)
• No changes to excluded files: AGENTS.md, PLAN.md, test/AGENTS.md, playwright.config.js, package.json, .stylelintrc, postcss.config.js, test/vrt/api-manifest.json, test/vrt/*.spec.js, src/_dropdown.css, src/_grid.css, src/_util.css, src/chota.css.

[jenil]

Closing — superseded by #188. This PR contained only the D2 (CSS source) half of #137. The complete change (D2 CSS + D3 tests/fixtures + the nav-logo-full-height.html inline-rem fixture conversions needed for VRT to pass) was merged as #188, which targets v1 directly with the full work/137-root-font-tests branch. #137 is complete (merge SHA 9b9aee0).