Rebuilt square-feet, percentage-change, and gradient pages to the BMI-style IG pattern with ten-locale copy.

Date: 2026-08-06 20:04 Summary: Rebuilt square-feet, percentage-change, and gradient pages to the BMI-style IG pattern with ten-locale copy.

[question] In /Users/xuli/vscodeai/onlinefreetools, rebuild these EXISTING calculator pages to match IG pattern in howToCalculateBmiPage.ts (helpers: renderToolIgSections, renderToolReferencesSection from src/pages/site/toolContent.ts).

Tools

square-feet — src/pages/squareFeetPage.ts + tool_squarefeet_*
how-to-calculate-percentage-change — src/pages/howToCalculatePercentageChangePage.ts + tool_percentage_change_*
how-to-calculate-gradient — src/pages/howToCalculateGradientPage.ts + tool_gradient_*

Specs

Read work-tasks/{slug}/02-tool-info.md and 03-locale-briefs.md.

square-feet

Keep unit conversion calculator UI
How + Formula + Example + Use cases (real estate / flooring / renovation — not generic unit converter fluff)
References: NIST or other unit conversion authority (≥1)
All 10 langs independently

percentage-change

Keep calculator
Full numeric example + business/data use cases
Formula visible; FAQ on percentage points vs percent
References optional but good (e.g. educational math source)
All 10 langs

gradient

Keep calculator if present
Clear multivariable gradient formula
Use cases optimization/ML
References: math education sources
related stays percentage-change, roi per catalog
All 10 langs

Rules

Full function comments in page TS
description ≥120
Update scripts/site/i18n.mjs home cards when titles change
NOT isomorphic ten-lang paste
Do not modify BMI, headers, text-diff, markdown pages
Run npm run lint:seo and fix your failures

Return files changed + gaps.

[try to solve] Rebuilt three pages to the BMI IG pattern: renderToolIgSections (How / Formula / Example / Use cases) + renderToolReferencesSection; calculator UI kept.

square-feet: L×W unit switching kept; results show both sq ft and m² (NIST factor 0.09290304); real-estate/renovation use cases; NIST SP 811 reference; FAQ covers net vs gross area and non-appraisal.
percentage-change: formula (new−old)/old×100; example 80→100 = +25%; business/data use cases; percentage-points FAQ; Relative change reference.
gradient: kept multivariable ∇f per user request (not two-point slope); demo function evaluation UI; optimization/ML use cases; Wikipedia Gradient + Khan Academy; related remains percentage-change, roi.

Ten-locale independent copy written to src/site/i18n/*.ts; home-card titles/descs synced in scripts/site/i18n.mjs. npm run lint:seo passed.

Gaps: (1) work-tasks gradient 02/03 leaned two-point slope; implementation kept multivariable calculus per user instruction; (2) ar/ja/ru still recommend native review; (3) 03 round checkboxes unchanged (not requested); (4) square-feet remains an L×W area tool (not a pure area-value bidirectional converter).

[actions]